B.pharm

No, you are not eligible for this course. B.Pharma basic requirements are (10+2) Science, but you are a commerce student, so you are not eligible for the B.Pharma.

No, you are not eligible to do B.Pharma because you are from commerce stream. You should have had science stream in 12th for that.

Here's the list: https://www.shiksha.com/medicine-health-sciences/pharmacy/colleges/colleges-west-bengal.

Listed below are the minimum criteria which candidates interested in pursuing the course are required to fulfil, in order to be eligible to apply for the course-
Successful completion of the 10+2 level of education in the Science stream, completed from a recognized board/university.
A minimum aggregate score of 50% (45% for SC/ST candidates) at the 10+2 level.

There is no option at BITS for changing B.Pharma to BE.

Which exam are you referring to as mostly all national level & state level exams have already been conducted.

Please share your GMR for a better answer.

After completing a graduation degree, you can work at government hospitals, private medical shops & private hospitals/clinics. You can also start your own consultancies & medical shop. The students can work in a Pharmaceutical company or CAN practice as a Pharmacist.

Yes, I am listing top B Pharmacy colleges under UPSEE. Please do check the list below:
Galgotias University, Greater Noida
HIMT College of Pharmacy, Greater Noida
Dr. A. P. J. Abdul Kalam Technical University, Lucknow
Innovative College of Pharmacy, Greater Noida
Banaras Hindu University, Varanasi
Chhatrapati Shahu Ji Maharaj University, Kanpur
Azad Institute of Pharmacy & Research, Lucknow.