A.SELECT学号RORMSCWHERE课程号='C1'AND课程号='C5'
B.SELECT学号RORMSCWHERE课程号='C1'AND课程号=(SELECT课程号FROMSCWHERE课程号='C5')
C.SELECT学号RORMSCWHERE课程号='C1'AND学号=(SELECT学号FROMSCWHERE课程号='C5')
D.SELECT学号RORMSCWHERE课程号='C1'AND学号IN(SELECT学号FROMSCWHERE课程号='C5')