BCA

No, B.Tech has more preferable job option. At this time MCA market is totally down.

All three degrees are equally good. It is difficult to compare BCom with BCA as both are graduations from different fields. If you compare BCom with BCom (Hons), I will recommend Hons degree over pure vanilla degree because of its more market acceptance. You are advised to chose degree based on your interests to excel.

Abhaty !It is suggested to select the course based on your interest.study about the course,its scopes and then choose it based on your comfortness in that discipline.both are doing equally good in their professional but choose the institute carefully,here are some of the premier institutes where you may get admission:
1.University of Delhi
2.SRM
3.Lovely Professional University
Lovely Professional University is doing exceptionally well,they along with good placements has set a new standards in field of education.They work while collaborating with industries benefiting their students in placements.

This will help you.
http://entrance-exam.net/bca-vs-bsc-it-which-course-is-better/

You can do B.Sc IT.

Yes, you can. Go for it.