Which one should i pick? I need a 6th course for my first term in college and they are all pretty interesting.
In terms of usefulness, I'd say Sociology, PoliSci, and then Anthropology. In terms of interest, I'd pick Sociology, Anthropology, and PoliSci.
Anthro and Socio are really pretty much the same science, just applied with different variables. Poli Sci is also the same premise, but far more perverse. I'd say Anthro is the biggest picture of the three, and thus the best introduction to the other two.
It depends on what kind of political science course it is. I have taught several political science courses at the community college level. There is a big difference, for instance, in a course such as international politics and one in American government. It has been my experience that students can get very interested in international politics or even state and local government, but the interest level in American government is usually low. If it's an American government course, the chances are you might not be very interested in it, although it still might be very useful to you.