(33)～(34)题的关系代数操作基于如下的关系R和S：

查询选修了课程号为’C2’的学号和姓名，若用下列SQL的SELECT语句表达时，哪一个是不正确的 ( )

A．SELECT S#，SNAMEFROMS WHERE S#=(SELECTSS# FROMSC WHERE C#=’C2’
B．SELECTS#，SNAMEFROMS，SC WHERES#=SS# AND C#=’C2’
C．SELECTS#，SNAME FROM S，SC WHERES#=SS# AND C#=’C2’ORDER BY S#
D．SELECTS#，SNAME FROM S WHERE S# IN (SELECT S S# FROM SC WHERE C#=’C2’