Which of these courses will be most useful for a future creative writer?

Social Anthropology seems like the best bet to me out of those options. You learn to understand the differences between different cultures and societies as well as how or why they may have been formed, and that may help you to understand how to portray or comment on people of various and diverse backgrounds in your writing. It also enables you to encompass a large range of attitudes and beliefs by being able to understand multiple perspectives of a societal issue.

Also, the other courses only seem loosely linked to creative writing in general, and would perhaps be more suited to broadcasting, journalism and formal writing.

I don't want to take Creative Writing. Instead, I want to learn something else that could complement my future creative writing. What's your opinion if I had to choose only one of these courses below?

1) Social Anthropology
2) International Political Economy or International Politics
3) Media and Communications (mainly theory/critical analysis and not the practical/professional aspects)
4) Law
5) Psychology

Thank you for this. I have to admit, I was more inclined to choose that first one too, but there was another part of my mind saying I should also keep my options open in case I end up being a non-fiction writer (or a citizen journalist) instead of a creative writer.

I don't want to take Creative Writing. Instead, I want to learn something else that could complement my future creative writing. What's your opinion if I had to choose only one of these courses below?

1) Social Anthropology
2) International Political Economy or International Politics
3) Media and Communications (mainly theory/critical analysis and not the practical/professional aspects)
4) Law
5) Psychology