Answer:
Rainsford finds a large gothic-like mansion in the middle of the jungle.
Bivalves, compressed bodies enclosed by a shell consisting of two hinged parts. Bivalves include clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater.
Enjambment - the sentences do not finish with the end of the line.
Simile - "like a slackened drum"
Maybe even hyperbole, since it is an exaggeration.
The answer is D: word choice and length of sentences.