The correct answer is metaphor.
A metaphor is a rhetorical figure of speech where two or more things are symbolically compared, without using the words such as like or as (because that would be a simile). This whole poem is symbolical/metaphorical - it talks about the passage of time and how everything is transient and fleeting.
He is used to the kgb knocking on his door to ask him challenging accusing questions
Actually..... all of them are correct!
The difference is whether the word "the orchestra" needs a plural or singular verb. In American English a singular verb is needed (so American English would only accept options a) and c) ) but in British English both forms are acceptable: so in British English all four sentences are correct.
In the poem The Raven, the speaker seems paranoid and desperate. he claims to be hearing strange noises from outside his room as well as claiming that the spirit of his loved one, Eleanor, has come back to him.