why are American students usually under pressure o

单项选择题

Questions 17 to 20 are based on the following introduction of American students. You now have 20 seconds to read Questions 17 to 20.

why are American students usually under pressure o{ work

A．Because their academic performance will affect their future career in the future.
B．Because they are heavily involved in student affairs.
C．Because they have to observe the university discipline.
D．Because they want to run for positions of authority.