No Biology isnt compulsory for the KVPY exams, its upto you on the subbjects that you want to choose. You can go with Physics Chemistry and Mathematics\Biology or even all 4 any combination you can take. For SA yes Biology is compulsory but for SB and SX even PCM combination is okay.

Refer to the website below for more information...

https://school.careers360.com/articles/kvpy

https://school.careers360.com/articles/kvpy-eligibility-criteria

Best wishes. Thank you.