有一个关系模式employee(name,department,phone_number),下面哪句话允许user1可以修改phone_number列的值
A.GRANT MODIFY (phone_number) ON TABLE employee TO user1
B.GRANT ALTER (phone_number) ON TABLE employee TO user1
C.GRANT UPDATE (phone_number) ON TABLE employee TO user1
D.GRANT REFERENCES (phone_number) ON TABLE employee TO user1
正确答案是C