Exam

Since you failed to qualify in general category as the cut-off was 74, therefore, you will not be able to get any college like NIT, IIT, IIIT, etc.
You can prefer any state level entrance exam which can lead to government colleges if you score very good marks. Not just cut-off marks. You can also go

Hello Rohan,
Don't Panic if you haven't studied full theory syllabus. Focus on what you have Studied. Revise that concept. Practice as many questions as you can. Remain calm. Devote your full remaining time to studies till the exam. As 4 days are coming study as much as you can. Clear your concepts

I think there is no "best" thing in studies. Only we are the one who makes everything better through our hard work and dedication. But as to answer your question, in my opinion, FIITJEE has the best faculty members all over India. here are the reasons:
1. The test series of FIITJEE is up to the level

Although OBC comes under the reserved category, but its cut-offs are still very high. Your chances for top 10 colleges seem to be very low.