Hello Koushik, 

Since you have asked for Commerce Student, I would suggest that it is better to opt for Stats, since it would help you in the subject you have chosen to pursue. Stats with the other courses offered under Commerce goes hand in hand. However, if you do not wish to pursue Commerce in higher studies, and you wish to do something more practical that offers a high-end salary right after graduation, you may go for Computer Science.

Good luck!