I got 81% in 2nd PUC (PCMC). So, which branch is good in engineering?

Depends upon on your choice and nature. If u prefer core field then go for civil or electrical or mechanical and if u prefer IT then CSE or ECE or may be EEE good. as u know that every field has its own importance. CSE may the the best choice if u like IT and EE may the best choice if u like core f

It completely depends on your field of interest. Since you have computer science as your optional subject, you should prefer computer science or information technology. Computer science has had the highest cut-offs in the previous years. There are more options available; do check them out too.