检索“至少选修课程号为’C1’的学生姓名(SNAME)”的SQL语句是
A.SELECT s. sname FROM s, sc WHERE c. cno=’C1’
B.SELECT s. sname FROM s, sc WHERE c. cno=’C1’AND s. sno=sc. sno
C.SELECT s. sname FROM s, sc FOR c. cno=’C1’
D.SELECT s. sname FROM s, sc FOR c. cno=’C1’ AND s. sno=sc. sno