查询所修课程成绩都大于等于85分的学生的学号和姓名,正确的命令是
A. SELECT学号,姓名FROM student s WHERE NOT EXISTS (SELECT*FROM score sc WHERE sc.学号=s.学号AND成绩<85)
B. SELECT学号,姓名FROM Student s WHERE NOT EXISTS (SELECT*FROM score sc WHERE sc.学号=s.学号AND成绩>=85)
C. SELECT学号,姓名FROM student s,score sc WHERE s.学号=sc.学号AND成绩>=85
D. SELECT学号,姓名FROM student s,score sc WHERE s.学号=sc.学号AND ALL成绩>=85