Hey there

As I have searched there is no detail about whether we can for masters at the fifth semester of BCA. I think only after completing Bachelor of Computer applications you can do master of computer application. Moreover, mentioned below are the eligibility details for master of computer applications:

1. The candidate must have completed graduation in computer applications computer science or any other related field with  minimum 50% marks in aggregate.
2. The candidate must have studied mathematics as compulsory subjects in class 12.

For more:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.careers360.com/courses/mca-master-of-computer-applications/amp&ved=2ahUKEwjI8JnegbHzAhWL7XMBHenKASEQFnoECBEQAQ&usg=AOvVaw2I6o-CBsUeIXmuq866JS_p&ampcf=1