【题目】 删除计算机系学生（在student表中）的修课记录（在SC表中）的语句，正确的是（　　）。

DELETE  FROM SC JOIN Student b ON S.Sno = b.Sno
　WHERE Sdept = ‘计算机系’

DELETE FROM SC FROM SC JOIN Student b ON SC.Sno = b.Sno
　WHERE Sdept = ‘计算机系’

DELETE FROM Student  WHERE Sdept = ‘计算机系’

DELETE FROM SC WHERE Sdept = ‘计算机系’