Go through as many threads as you want, talk to as many seniors as you can, in the end you'll realize that this age old question has the same age old answer: It depends on your interest!
So, when you're choosing between Political Science and International Relations, or between any other subjects for that matter, just ask yourself which one subject gets you going. Since you're a business graduate you might find Political Science a difficult option because its very lengthy and requires a lot of patience to swim through the ocean of political philosophies, come out of it and still have the motivation for making another dive for paper B. Only if you're interested will you be able to tie the knot with Pol Science. International Relations on the other hand is, well, if i could say it in one word, its in vogue! Even if you don't have a background, you still have a background. (through news, social media etc) And its not boring. And its way shorter than Pol Science.
Indo Pak History is a very popular choice.
Journalism/Sociology are both concise and straightforward!
Your missing subject depends upon your choice between Pol Science and IR. Public Administration syllabus overlaps with Pol Science and International Law is opted by those going for IR.
So, happy match-making!