Until Recently it was Thought that Ink used Before the Sixteenth Century did not Contain Titanium.

Question: Until recently it was thought that ink used before the sixteenth century did not contain titanium. However, a new type of analysis detected titanium in the ink of the famous Bible printed by Johannes Gutenberg and in that of another fifteenth-century Bible known as B-36, though not in the ink of any of numerous other fifteenth-century books analyzed. This finding is of great significance, since it not only strongly supports the hypothesis that B-36 was printed by Gutenberg but also shows that the presence of titanium in the ink of the purportedly fifteenth century Vinland Map can no longer be regarded as a reason for doubting the map's authenticity.

The reasoning in the passage is vulnerable to criticism on the ground that

1. the results of the analysis are interpreted as indicating that the use of titanium as an ingredient in fifteenth-century ink both was, and was not, extremely restricted
2. if the technology that makes it possible to detect titanium in printing ink has only recently become available, it is unlikely that printers or artists in the fifteenth century would know whether their ink contained titanium or not
3. it is unreasonable to suppose that determination of the date and location of a document's printing or drawing can be made solely on the basis of the presence or absence of a single element in the ink used in the document
4. both the B-36 Bible and the Vinland Map are objects that can be appreciated on their own merits whether or not the precise date of their creation or the identity of the person who made them is known
5. the discovery of titanium in the ink of the Vinland Map must have occurred before titanium was discovered in the ink of the Gutenberg Bible and the B-36 Bible

Until Recently it was Thought that Ink used Before the Sixteenth Century did not Contain Titanium. – is a GMAT critical reasoning topic. This GMAT Critical Reasoning topic has been taken from the book ‘ Manhattan Prep's GMAT Foundations of Verbal, 7th Edition​’. In this particular topic, candidates are asked to select the most appropriate reasoning which is vulnerable to criticism. In this question, the candidates need to provide an option that supports the argument provided in the passage. GMAT critical reasoning tests the logical and analytical skills of the candidates. The GMAT CR section contains 10 -13 GMAT critical reasoning questions out of 36 GMAT verbal questions.

Answer: A
Explanation:
This is a GMAT critical reasoning question containing five answer choices. So we are looking for something that is implied in the argument. In case it is wrong or maybe disable the statement.

The argument is: the finding of titanium in ink before 16 century help:
- Identify the printer identification of B36: Gutenberg
- Identify the date of the Vinland map precisely with no doubt anymore: 15 century

To weaken: We need to prove that regardless of the presence of titanium in the ink, we can still identify the identification of printer of B36 and the publish date of Vinland map precisely

Let's go through the assumptions that suit the most with the given argument:

1. the results of the analysis are interpreted as indicating that the use of titanium as an ingredient in fifteenth-century ink both was, and was not, extremely restricted. – The use of titanium as an ingredient in fifteenth-century ink both was, and was not, extremely restricted. This option weakens the arugument as the passage says that titanium was found in the ink. Hence, this is the correct option. 
2.  if the technology that makes it possible to detect titanium in printing ink has only recently become available, it is unlikely that printers or artists in the fifteenth century would know whether their ink contained titanium or not – This option also not in context with the passage. This talks about the technology of the recent times but the passage does not sugest any such thing. Hence, we can consider this as incorrect. 
3. it is unreasonable to suppose that determination of the date and location of a document’s printing or drawing can be made solely on the basis of the presence or absence of a single element in the ink used in the document – The passage never says that the Vinland map is from the 15th century just because titanium was discovered in the ink. It can be inferred from the argument that the discovery of titanium had caused a sense of doubt on it's authenticity. All the other clues might have been pointing to the fact that it was made in the 15th century. So, C is wrong
4. both the B-36 Bible and the Vinland Map are objects that can be appreciated on their own merits whether or not the precise date of their creation or the identity of the person who made them is known. This is the best option. The boldface indicates that regardless of the presence of titanium, B36 and Vinland map can prove their worthiness on their own
5. the discovery of titanium in the ink of the Vinland Map must have occurred before titanium was discovered in the ink of the Gutenberg Bible and the B-36 Bible.- From the argument, it seems that titanium was discovered in the ink of the Vinland map before it was found in the two Bibles. However, this is not the debate and hence it is Out of Scope. 

Suggested GMAT Critical Reasoning Questions

• It is Difficult to Keep Deep Wounds Free of Bacteria.
• The Marison County Police Department recently implemented a new traffic safety program
• Because no employee wants to be associated with bad news in the eyes of a superior
• According to a study, after a week of high-altitude living, twenty men had slimmed down.
• Shelby Industries Manufactures and Sells the Same Gauges as Jones Industries.
• Building a space station, in which astronauts would live for a considerable time
• The interview is an essential part of a successful hiring program because, with it, job applicants who have personalities that are unsuited to the requirements of the job will be eliminated from consideration.
• According to a recent study, retirees in the United States are four times more likely to give regular financial aid to their children as to receive it from them.
• Using oil-based paints to paint walls or furniture requires the use of turpentine and each coat takes a long time to dry.
• President of the United States: I have Received over 2,000 Letters on this Issue, and the Vast Majority of them Support my Current Position.
• Roland: The alarming fact is that 90 percent of the people in this country now report that they know someone who is unemployed.
• TOMMY: That telephone always rings when I am in the shower and can’t hear it.
• A major network news organization experienced a drop in viewership in the week
• Seeking a Competitive Advantage, Some Professional Service Firms
• Between 1980 and 2000 the sea otter population of the Aleutian Islands declined precipitously.
• Critics have Long been Puzzled by the Inner Contradictions of Major Characters in John Webster’s Tragedies.
• Few of the corporate contributions to the earthquake relief fund, aside from Pterocom
• If the books have been cataloged last week, why haven’t they been placed on the shelf?
• French cuisine is highly regarded all over the world.
• The Marison County Police Department recently implemented a new traffic safety program