Science

No, it is rarely possible.

Yes, if you wish you can select any optional subject.

Most of the universities will not allow study in two degrees of B.Sc and BCA simultaneously. However, you may approach targeted university for clarification on subject with registrar of university.

You should try for any other university like Amity and Sharda, kindly do not take me wrong because DU will not accept you in any condition.

You may try another college for B.Sc. like A.U., BHU and ECC if you are trying in a private college.

I think you should do a technical course like M.Sc. in radiology, etc.

Hi Ahswine,
Please refer to the university websites to check the programs they offer. What you want to study is something you must decide, identify your areas of interests, likes and dislikes, speak to the university counselors and also your teachers regarding subject choice. Please check the program list here
http://distance.bharatividyapeeth.edu/default.aspx
http://www.unipune.ac.in/administration_files/BCUD.htm
Hope it helped.

Following are career options for PCBM students after 12th class
(a)Medical or Dental or Physiotherapy or degree is alternate medicines
(b)B.Tech
(c)BCA
(d)B.Sc Physics, Chemistry, Maths, Statistic, Zoology and Botany
(e)B.Sc Architecture
(f) B Pharmacy
(g)B.Sc Forensic Science
(h)Biotechnology
(I)BBA
(j)BCA
(k)B.Sc Microbiology
(l)B.Sc Nursing
(m)Hotel management
(n)Fashion Designing or Fashion Technology
(o)Change to Humanities or Commerce Stream
You have all options available, you may chose any based on your interest to excel.