Answer: The third choice
"Not a flower, not a flower sweet,
On my black coffin let there be strown:"
Flowers on gravestones and coffins alike are symbols of love and respect, None of the other choices really embody the beg of the question.
Unrequited is defined as "(of a feeling, especially love) not returned or rewarded."
Since the it says a flower would not be laid on the coffin, it is unrecuperated love and respect, denied by others.
#platofam