B.Sc

Registration and admission test has been taken place long ago. Sorry, you can't apply in Presidency University this year.

Please refer to the link provided below for details regarding admissions for MBA from Faculty of Social Science, Dayalbagh Educational Institute. Information regarding eligibility, fee structure, placements etc. is mentioned at this link. Regards.
https://www.shiksha.com/mba/course/master-of-business-administration-faculty-of-social-science-dayalbagh-educational-institute-agra-288348

Admission will be according to Sequence number that has been provided with GMR. Rank 60 is high and chance is low to get through. Though WBJEE and NEET counselling will take place before PUBDET counselling. So, there might be a chance, if candidates with better ranking wouldn't appear for the PUBDET counselling which is going to be held in mid-July.

You need to have minimum 50% marks for admission in B.Sc Physics.

Every college has different criterion, so kindly check the same with the college itself. Usually, it is the date of birth.

Yes, you surely can apply for a job in defense services once you complete B.Sc Mathematics.