Hello purnendu, congratulations on your marks sir! hope you are doing well sir! 

sir as per your marks if you want to continue your carrer in science then you do btech from any govt or private institute! Or else you can do BCA which is related to computer applications Only if you are intrested in study of computers! Doing BTech course will help to focus on upcoming future! Doing btech course in any stream would definetly help you! 

Al the best..