下列删除计算机系学生的修课记录的语句,正确的是 ( )
A. DELETE FROM SC JOIN Student b ON S.Sno = b.SnoWHERE Sdept = '计算机系'
B. DELETE FROM SC FROM SC JOIN Student b ON SC.Sno = b.SnoWHERE Sdept = '计算机系'
C. DELETE FROM Student WHERE Sdept = '计算机系'
DELETE FROM SC WHERE Sdept = '计算机系'