从Student表检索年龄为20岁的学生信息，已知年龄字段是数值类型，最规范的SQL语句是（)。

A.Select * From Student Where Ssex='男' Or Sage<'21'

B.Select * From Student Where Ssex='男' Or Sage<21

C.Select * From Student Where Ssex=男 And Sage<'21'

D.Select * From Student Where Ssex='男' And Sage<21

A.SELECT * FROM StInfo WHERE 性别='男' OR 年龄<20

B.SELECT * FROM StInfo WHERE 性别='男' OR 年龄<'20'

C.SELECT * FROM StInfo WHERE 性别=男 AND 年龄<'20'

D.SELECT * FROM StInfo WHERE 性别='男' AND 年龄<20

A.Select MAX, MIN, AVG Sage from Student

B.Select MIN, MAX, AVG Sage from Student

C.Select MAX(Sage),MIN(Sage),AVG(Sage) from Student

D.Select MIN(Sage),MAX(Sage),AVG(Sage) from Student