I am a B.Com student & doing Diploma in mass communication along with. Which course should I go for among MBA & PGDMC?

PGDM is the best option after B.Com. You are already doing your Diploma in mass communication, it will enhance your vocabulary and vocal skills which is the basic requirement for management program. Now, you need to appear for one of the exam like: MAT, CAT, CMAT or ATMA. You should have above 50%

You should go for PGDMC as it is explicitly covering courses on mass communication. MBA will cover other courses too as you have prior knowledge in mass communication, PGDM - C is a better option for you.