这个问题的答案是C, visit做及物动词。没错,字典上是既可以用作及物动词又可以用作不及物动词,需要带宾语时用做及物动词,不需要带宾语时就用做不及物动词。比如:
I went to visit my teachers on my first day of summer vacation.--及物动词,宾语是my teachers。
I went to my former school just to visit.--不及物动词,不带宾语。