Hello Anurag, 

Based on your different ranking, firstly I would recommend you to apply for college using your rank under category OBC-b. It will improve your chances of getting admission in some of the top college these tough competition.

Now some of the college where you can apply using your OBC-b rank, 

University of Calcutta

Jadhavpur University

Maulana Abul Kalam Azad University of Technology, Kolkata

University of Kalyani, Kalyani

Government College of Engineering and Leather Technology, Kolkata

For more colleges based on your rank, you can check the link given below:-

https://engineering.careers360.com/college-predictor-result/50034?s=80721883081529079247

To search college based on your other results you can use WBJEE college predictor.

Hope you find this information useful. Have a great future ahead.