If you really want to take the written test, you need to understand how the entire process works.

You can choose;
[*]IR - Easy to score, lot of relevant study material available.
[*]Gender Studies - Easy to prepare, examiners cant ask too many questions.
[*]Sociology - Examiners can only ask a few questions - so easy to prepare
[*]Indo-Pak History - You'd already know more than half the syllabus.
[*]Town Planning & Urban Mangement - Very limited course, easy to prepare, easy to write about.

Hope this helps