题中的三张表,检索选修课程“C2”的学生中成绩最高的学生的学号。正确的SELECT语句是(10.0分) A. SELECT S# FORM SC WHERE C#=“C2” AND GRAD>= (SELECT GRADE FORM SC WHERE C#=“C2”) B. SELECT S# FORM SC WHERE C#=“C2” AND GRADE IN (SELECT GRADE FORM SC WHERE C#=“C2”) C. SELECT S# FORM SC WHERE C#=“C2” AND GRADE NOT IN (SELECT GRADE FORM SC WHERE C#=“C2”) D. SELECT S# FORM SC WHERE C#=“C2” AND GRADE>=ALL (SELECT GRADE FORM SC WHERE C#=“C2”)