Hello aspirant, hope you are doing good.

Firstly, congratulations for your preparatory rank in SC category, you know this is a bonus chance given to you, make good use of it. As you might be knowing, preparatory ranks are not real ranks, these are the ranks that have been given for vacant seats in IITs , to tutor for a year, and based on the examination in the next year, your seat will be confirmed.

So I'll mention some of the IITs that offer preparatory courses:

1.IIT Roorkee

2.IIT Delhi

3.IIT Mandi

4.IIT Guwahati

5.IIT Kharagpur

6.IIT Bhubaneshwar

7.IIT Patna

8.IIT Madras

9.IIT Bombay

10.IIT Hyderabad

If you want to know about all the possible colleges you can get into with your JEE Advance rank, you can get it here:

https://engineering.careers360.com/jee-advanced-college-predictor?icn=QnA&ici=qna_answer

Hope this helps you. Good Luck!