I think it's C. Heavy means the sigh was long, and obviously loud. Wind through a tomb is used as a metaphor that the sigh was lonely. Lonely means nobody is there, and nobody is there to hear wind go though a tomb, and anyone in the tomb can't hear, because, well, they're dead.
Answer:
Phrase
Explanation:
There is no subject-verb.
This is a prepositional phrase acting as an adverb.
Hope this helps:)
Attacked is past tense and past participle is attacks