For MSc courses at Calcutta University, one need to have completed there BSc with Hons. mandatorily. You can appear for the examination such as IIT JAM, Central University etc which don't have this Hons. criterion. Also in CU you can apply for the LLB course as well as it didn't have the Hons criterion. But for MSc you aren't eligible.

For more information regarding Calcutta University you can consider the link below:

https://www.careers360.com/university/university-of-calcutta-kolkata

I hope this helps. Wish you a great eve!