Exam

Yes, for bio students Allen is the best option.

At this time, Resonance is best for IIT preparation.

In my opinion, resonance is best for IIT preparation for freshers as well as repeaters, as it provides a better atmosphere for study for all.

First of all, thank you for asking question as this is one of the most common doubt of students . Let me clear your doubt
Your rank should be less than 60k and this rank varies from category as you already know. Not only your rank but your percentage also needs to be good for getting CS in GL Bajaj . If due to any reason you don't get good rank in UPSEE exam then you can also take admission directly in GL Bajaj, but for CS your percentage should be more than 80%.

In my opinion resonance is best for IIT preparation for freshers as well as repeaters.

If you are interested, then you can otherwise don't waste your time and money there. Best of luck.

Kotak is the best in term of IIT preparation. If you spending money then Kotak is the best option as it has a better atmosphere for study and competition.

For JEE Mains preparation, I suggest you Resonance.