You can apply both of them, but notice the 所謂的“最後行為規則”, that means if your H-1b approved after your OPT, you are H-1b, or otherwise. See today Wenxuecity new in detail. I suggest your school applies H-1b, instead you apply OPT. You don't have to leave here to change your status. You can work on your thesis after you get your H-1b.