题目如图,∠ACB=90∘\angle ACB=90^{\circ}∠ACB=90∘,CD⊥ABCD\bot ABCD⊥AB于点DDD,点AAA到CDCDCD的距离是( )A.线段ACACAC的长度B.线段BCBCBC的长度C.线段CDCDCD的长度D.线段ADADAD的长度知识点:点到直线的距离章节:未标注