I'm a student of be mechanical and i want to go for mtech so which branch to take that has better scope i have cad/cam in mind.

I'm a student of be mechanical and i want o to mtech but i m confused which branch to take which has better scope.i have cad/cam in mind.so please suggest me.and also is good to do mtech from private collage like jecrcu cause i was not able to qualify gate.