AoA,
I'm engineering graduate and I am going to appear in css 2017, my optional are as follows:
IR
I.law
Environmental science
Sindhi
Us history/ Indo pak history.

I'm unable to decide whether I should go for us history or indo pak history. Though, I'm very much familiar with the later, yet I'm hesitant to opt it because: one, it is considered as a low scoring subject.
Two, as I'm opting IR and I.law so I'm told that us history would be better to be opted alongwith above mentioned subjects.
Three, indopak history is much lengthier than us history.

Considering all this, please guide me how is my overall combination? And secondly, should I go for us history or indo pak?

I'll be indebted to you for your kind advice and guidance.
Regards.