欲回收系统中已存在用户 xiaoming 在表tb_course上的SELECT权限,以下正确的SQL语句是( )。

A. REVOKE SELECT ON tb_course FROM ximoming@localhost
B. REVOKE SELECT ON xiaoming FROM tb_course
C. REVOKE xiaoming ON SELECT FROM tb_course
D. REVOKE xiaoming @locallost ON SELECT FROM tb_course