C. is the correct answer.
C is the only answer choice that refers to the future ("a sign, he said, a sign"). The rest of the answers refer to things happening in the present in the story, with almost no reference to the future of the plot.
A ghost delivers a supernatural kiss of death
You haven’t attached the sonnet, so I can only guess at what you are referring to. But I believe I had this same sonnet last year in my English class, if it is the one describing his love, then it is C.
