B.A

There is no negative marking. Group discussion and interview is mandatory to get an admission.

B.A. Hons in vocal music is offered by RBU, Kolkata. For more information about this:
https://www.shiksha.com/arts-fine-visual-performing/music/course/b-a-hons-in-vocal-music-rabindra-bharati-university-b-t-road-Kolkata-269612

Go for M.A. in English literature so that you will be more into the same field.

Hello Zai,
Please go to link below for all the colleges having this course and their eligibility criteria:
https://www.shiksha.com/banking-finance-insurance/colleges/diploma-courses-Delhi
All the best.

The duration of this course is 3 years.

No, it is not compulsory. Some colleges take admission on the basis cutoff list or merit basis. Check this link :-
https://www.shiksha.com/arts-fine-visual-performing/music/course/b-a-hons-in-music-hindu-college-north-campus-delhi-north-campus-52588

This would depend on your interest areas and career aspirations. In case you intend to pursue a career in Economic/Equity research / financial journalism/academics area then M.Sc Economics is better. However, if you want to move into a career in analytics & data sciences, then the other two courses are better.