It would be difficult to provide you the exact infrmation as cutoff varies every year depending on the various factors like difficulty level of the exam, Number of candidates appeared for the eformance of the candiadtes etc. 

As per the previous year cutoff, The maximum closing rank of WBJEE was around 34713 for CSE branch as SC category. You can also refer the below given link to check the other branches cutoff.

https://engineering.careers360.com/articles/wbjee-cutoff

Good Luck!