This is a general confusion with students. SInce students would like to keep all the options open and not be restricted to just one stream later post 12th.
Here doing a self analysis is important and most importantly being honest is important.
Are you a technical person???
Do you like to handle machines and explore them???
Does the human body and mind intrude you???
Do you like Research???
Generally I would advise students to opt for all the 4 subjects and then based on their interests choose a stream further on
Options under PCM includes: