Which stream should I choose among commerce and science to pursue B.Sc.?

You choose Science only for doing B.Sc. With Commerce you get B. Com. degree. However, even if you had Science subjects in school but have not developed a liking for them then you can opt for Humanities related subjects in college Asif.

obviously u should go for Science

Obvio Science after 10 +2 u will get graduated with B.Sc