For general knowledge, try to go through the current events of the last 10-12 months. I will recommend you to read about the current affairs related to politics, banks, economy, sports, industry, infrastructure, telecommunication, etc. You do not need to mug up every news story but be aware of them so that when you are asked about it you can at least give a brief. Also, learn about all the common general knowledge questions. You can buy general knowledge books or get help from YouTube.
You need to understand that the main trait of an MBA student is his/her confidence and communication skills. So, be prepared to face tricky questions and will test your knowledge and your ability to deal with pressure. Lastly, do not get nervous if you are not able to answer a single question. Be honest with the interviewer and do not lose your confidence.