关于溃疡性结肠炎，下列说法错误的是（）

A.本病常见于20～40岁

B.病变以直肠及乙状结肠最多见

C.病变常深达肌层

D.随病程延长，结肠癌发病率增加

E.可并有慢性活动性肝炎、关节炎、结节性红斑

I don’t think his success has a lot to do with good luck. It’s hard work ______ has made him what he is today.

A．which

B．that

C．where

D．why