Answer:
The sentence that is in inverted order with the subject underlined is sentence C.
Explanation:
Sentence C contains an expletive there. In this case, there is not grammatically related to the rest of the sentence. Expletives serve a function but do not have any meaning. In fact, if the expletive was removed, the meaning of the sentence would be left unchanged (1). The expletive is also called a dummy subject.
1) A big group was here last night