B.Com

After completing B.Com (Hons) you can do these things:
Chartered Accountant, Master of Commerce, Master of Business Administration (MBA in Finance), Certified Management Accountant (CMA), Certified Public Accounting, Association of Chartered Certified Accountants (ACCA), and Business Accounting and Taxation (BAT).

Hi Vaidik,
It's around $74,625 annually and is subject to change. This includes tuition, books, boarding, etc. Please check the website.
Here is the link:
https://www.bu.edu/questrom/admissions/graduate-programs/full-time-mba/tuition-financial-aid/

If you want to pursue a course related to business studies, BBA is a good option.

Certainty, yes. I would suggest St. Xavier's College if you are based out of Kolkata. Other options are Jadavpur University and the University of Calcutta.

You can pursue a photography course from NAP.

If you want to make a career in the photography field, B.Com or MBA won't do much good.

You can pursue a course related to photography in NAP.

Hi Shailja,
Here, you didn't confirm for which test you want to apply. So, it is not possible for me to guide you. Well, as you are in B.Sc. Final year and if you want to apply for any entrance test for M.Sc, then, you can apply for the entrance test. There is no age criteria for any of the entrance exam. Hope this solve your problem.
Best of luck!

Yes, you can, if someone in science stream. He or she may do commerce, arts and BBD is good for commerce.

No. You can get admission in first year though. You can only get lateral entry in BE or B.Tech. Your Diploma will be considered equivalent to 12th for B.Com.