C.recommended 为正确选项.
四个个动词,只有recommend 有这个用法,即recommend sb to do sth建议某人做某事
recommend that sb should do sth
recommend doing sth
suggest
1,suggest sth
2,suggest doing sth
3,suggest that sb should do sth
4,suggest one's doing sth
agree
1,agree with sb/sth
2,agree to do sth
3,agree that
approve
approve of sth
approve sth