Hello Teja,

All the subjects mentioned above are excellent and have almost equal probability of popping up in your PG-CET exam.

However if you find yourself evoked by the idea of viral replication or its mode of transmission then you should go for M.Sc. Virology.

But if medical microbiology attracts you the most then Applied Microbiology would help you score better marks.

Similarly, if you find exploitation of microbes for industrial use beneficial and intersting then you should opt for that.

However if you're still confused then go according  the weightage criteria or cut-off criteria for your respective subject of choice.

Hope this helps.

Goodluck!