Question about the budget, physical deficit, economics, your preference for institute if you are attending a common interview by many institutes like the interview of new IIMs, graduation course, experience
Most common: Introduce yourself and why MBA?

Question from graduation is almost sure if you are a fresher

If you are a Fresher then yes most of the questions will be based on your graduation. But yes, don't rely upon this myth too. Few pointers for your preparation :

*be thorough with the basics of all the courses that you have read during your graduation. People usually say that you must know only 2-3 subjects but kindly do not make this mistake because the interviewers might ask you anything to check your contingency handling skills. They might even ask you basic algebra questions just to check whether you might deal with statistics during MBA. So, get a gist of all the courses that you have read. 

*stay abreast with what is happening in your surrounding. Read newspaper daily. 

*know few of the new policies that have been implemented or amended. 

*there may be questions wherein your views on certain subject matters may be asked which you will have to defend confidently. For instance, some ethical dilemma might be given and your stance on that might be asked. One advice here -  do not deviate from your stance. Stay confident not adamant. 

*also, in the past there have been numerous instances when entire interview has revolved around hobbies or interests or passions of students for example football or cricket or anything of that sort. 

So overall, you have to be smart and prompt during those 15-20 minutes of interview. 

Prepare well!! 

All the best!!  For any other queries, feel free to ask.