salam,., bro yes you can join army after you have done your MBA in either Supply chain management or Finance.!!!
the proscess is same as of joining as a captain but you have to do another masters for commision..!!! on your selection (which should be done in army service corps or ordinance corps... they both are helping arms so you would have to miss the oppertounity of joining the battle but on the other hand u would be proud because you are the ones who would be supplying the army and our soldiers with ration, supplies , food and ammunition...

hope this satisfies your question.!!!
PS thats my first time replying to a thread in a helping way