选择一个对下列SQL语句描述正确的选项？ SELECT * FROM EMPLOYEES E JOIN DEPARTMENTS D ON (D.DEPARTMENT_ID=E.DEPARTMENT_ID) JOIN LOCATIONS L ON (L.LOCATION_ID =D.LOCATION_ID); A.会产生笛卡尔积 B.关联3张表不允许 C.都不对 DJOIN . . . ON子句用于多个表的连接