The correct answer is (C). There are two possible sentence as the Conjunctive adverbs join two independent clauses:
We needed to have a security report ;otherwise, we wouldn't go.
Or
We needed to have a security report. Otherwise, we wouldn't go.
Is that the full question can you show a picture of it ?
The tropics, underwater volcanic regions, the equator.
The correct answer is indeed a rhetorical question.
Rhetorical questions are those questions which don't necessarily need an answer. They just show us what somebody is thinking about, and it doesn't mean they want their question answered. This is what the excerpt above is about.
