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（ ）。
A、
DELETE FROM SC JOIN Student b ON S.Sno = b.Sno WHERE Sdept = .计算机系.
B、
DELETE FROM SC FROM SC JOIN Student b ON SC.Sno = b.Sno WHERE Sdept = .计算机系.
C、
DELETE FROM Student WHERE Sdept = .计算机系.
D、
DELETE FROM SC WHERE Sdept = .计算机系.