Is this factocy-----you visited last week A that B here C th

C.先把句子变成陈述语序,就是this factory is________you visited last week.可以看出主句缺少表语,所以要先选出表语,四个选项中只有C可以充当表语,因为先行词the one在从句中做visited的宾语,所以省略了关系词.

C
this factory 是主语，the one表语，省略先行词that

C 变为陈述句就是 this factory is the one you visited last week. the one 是现行词