Dear,

You can join INDIAN ARMY as an officer. However, you are not eligible for INDIAN NAVY and INDIAN AIR FORCE because you are from commerce stream and to apply for these you should have physics and mathematics as your subjects.

You can go in INDIAN ARMY as an officer from CDSE (combine defence service examination).

You are eligible to write AFCAT, CDSE, and there is entry in Indian Navy SSC logistics cadre. Basically B.com graduates are taken as Administration and Logistics cadres.

Hope this helps!