Hey Madhu !

It depends on the eligibility criteria of the university you are applying to. Some universities may prefer Mathematics or Computer Science for BCA, while others might accept any three subjects. Since you are from a PCB background, it is better to check the specific university requirements.

If the university allows any three subjects, you can keep Physics, Chemistry, and Biology. But if they prefer a different combination, you may consider replacing Chemistry with Biology if needed.

Hope it helps !