B.Sc

If you wish to pursue mathematics, go for msc mathematics and then NET to become a professor. Masters in statistics will lead you to be eligible for ISS ( Indian statistical Services) at par with IES.
Mba is the most traditional option.

Biotechnology is a applied bioscience stream which tries to imply technology biologically for upgradation of mankind. Biotechnology involves genetics, microbio, molecular biology in its field. As your hsc marks are good u can get into bsc.biotechnology curriculum. For btech, you hv to clear engineering entrances. All the best. Thank you.

Cat exam dekar aap top management colleges like IIM, SpJain, MDI gurgaon etc. me admission le sakte hain. CAT se definitely aapko top options milenge. CAT exam me koi minimum ya maximum age ya attempts nai hote. Jab aapko lage aap ready hain tab aap ye exam de skte hain. Ya to aao coaching join kr skte hain ya khudse bhi padh sakte hain. Choice is totally yours.

Among BSC BCA and engineering, doing BTec / BE is the best option due to long term career opportunities.