下列哪个语句实现将计算机系学生各科成绩置为0？

下列哪个语句实现将计算机系学生各科成绩置为0？

• A.update sc set grade=0 where sc.sno=student.sno and sdept= ’ cs ’
• B.update scset grade =0 where sno in(select sno from student where sdept=’ cs’ )
• C.update grade=0 from sc where sno in(select sno from student where sdept= ’ cs ’ )
• D.update grade=0 from sc where sdept= ’ cs ’