使用教学（STC）数据库，与如下查询语句等价的是（ ）。 SELECT *FROM Student WHERE Sdept = 'CS' EXCEPT SELECT * FROM Student WHERE Sage <= 19;
选项：

A:SELECT * FROM Student WHERE Sdept = 'CS' AND Sage > 19
B:SELECT * FROM Student WHERE Sdept = 'CS' AND Sage <= 19
C:SELECT * FROM Student WHERE Sdept = 'CS' OR Sage <= 19
D:SELECT * FROM Student WHERE Sdept = 'CS' OR Sage > 19