According to the official website http://www.banasthali.org/banasthali/wcms/en/home/hgher-education/ug_progs/index.html;jsessionid=222C260504450B1587BD56B8D9508C6C , for being eligible for BCA at Banasthali University, you should have completed your 12th with a minimum aggregate of 60%. It is 60% for General Category and 40% for Reserved Categories. The official website doesn't mention any specific subjects to study BCA. So if you are a Commerce student who has studied Mathematics and Computers in his 12th and you have secured the minimum aggregate required against your Category, then you are eligible for studying BCA from Banasthali University. Please check this page for more information: http://www.banasthali.org/banasthali/wcms/en/home/admissions/highereducation/index.html