关于Watch的问题如题啊The children went there to watch the iron tower

关于Watch的问题
如题啊
The children went there to watch the iron tower______
A to erect B be erected
C erecting D being erected
有的网友选C 而有的网友选D
他们的见解分别是:
1.watch 后可一跟动词原形,动名词,但不跟动词不定式.
erecting 是来修饰tower的 .首先B,D 是被动语态,不选； A的不定式用法不对.选C
2.being erected 用被动 选D
到底哪个是正确的答案.
我彻底晕了.