As per the rules & Guidelines of WBCS, a student appearing for the final year examination are also eligible to appear for the examination provided he/she needs to pass the final year examination on the application year.

So you are eligible to appear for the WBCS PRELIMS 2022, but keep in mind you have to qualify your B.COM (//B.COM) final semester on 2022 in order to be eligible for the subsequent rounds of WBCS.

For more information regarding WBCS you can consider the link below:

https://competition.careers360.com/articles/wbcs-notification

I hope this helps. Wish you a great day!