【单选题】

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 sc set 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’