Hello ,

Most of the universities in India allows you to choose only one extra subject which is also called Generic Elective and it includes almost every major subjects(depends on college to college)  like Computer science , Geography , chemistry , physics  , history and many more and you can also change the GE subject every year .

Always choose a subject in which you have interest , it should also be noted that choosing a GE for 4 semester might help you do MSC or MA in that subject in future (depends on subject to subject )

Hope this helps.