You must study, because the score is 10, but you don't know which elective course you can write then, so I suggest studying both. In this case, you can't write one in the exam, at least you can write another. You can also master it selectively. Or you can pay attention to the college entrance examination in previous years, which is often very helpful, so that you can be familiar with the form of questions and get familiar with them when you take the exam. Of course, if you are lazy, ask the teacher for information.