问题
The time he has devoted in the past years __________ the disabled is now considered to be__________ great value __________ him.
A:to help; of; for
B:to helping; /; to
C:to help; in; of
D:to helping; of; to;
B:to helping; /; to
C:to help; in; of
D:to helping; of; to;
正确答案是：
