One thing that I would like to add is that(take it as an advice) please don't ask others about which subject to opt and which not.You are the master of your own fate.The road to become a CSP has no shortcuts. No one can decide better for u except you,yourself.Subject selection can,without any doubt,become confusing,but it has a simple remedy to it.The most effective way is to pick up a subject,study its syllabus twice with utmost concentration and study its last 10 year past papers;and then if you find it interesting and if you reckon that you are inclined towards it, just go for it.What matters is your aptitude, interest and hard work. Forget about scoring trend;you never know what fpsc is up to..Just research well,work hard and rest leave it up to ALLAH.