the smoke come out of the building, my first thought was to call the fire department as

the smoke come out of the building, my first thought was to call the fire department as soon as possible.
A. Having seen
B. When seeing
C. When I saw
D. Seeing

A. Having seenB. When seeing(答案→)C. When I saw D. Seeing解析：考查句子结构。当分词做状语的时候，分词的逻辑主语必须的句子的主语，ABD三项的动词的逻辑主语都是人，而后面句子的主语是my first thought。两者不一致，故C正确。句意：当我看见烟从那个房子里出来的时候，我第一个想法就是尽快地打电话给消防部门。

我明天再问问老师，叫他解释下这个问题