As for which is simple, I'm not sure. Personally, I think ancient literature should be the most difficult, because it is too different from modern language, whether it is grammar or other aspects. As for comparative literature and legal politics, I still think legal politics is good, but it may be more difficult to test. Generally speaking, it is very difficult to take an interdisciplinary exam. Besides, what you are studying now has nothing to do with what you want to take the exam. This means that you must learn from scratch. Don't be scared by what I say, it doesn't mean you can't pass the exam. It's easy to change from science to liberal arts for postgraduate entrance examination, mainly by memorizing things, as long as you work hard from now on (I don't know how old you are this year). You'd better go to their graduate school website to see the required bibliography and some requirements. If you prepare according to the requirements of the institution you want to take the exam, your chances of getting in will be greatly improved.