@ Dia

You`re not bound to choose respective subject for any group. You can option any subject of your interest. Anyhow, You have to secure over all 600 marks for qualifing the exam. Explore the Pass standards for further assistance :

http://www.cssforum.com.pk/central-s...standards.html

If two aspirants acquire similiar marks and qualify the exam. They`ll be able to appear in interview regardless of subject differences.

Allah Nagheban,

__________________
ஜ иστнιπg ιš ιмթΘรรιвlε тσ α ωιℓℓιиg нєαят ஜ