The correct answer is A. both connotative and denotative.
There will be a lot of words where the denotative meaning should actually be ignored and the connotative observed, but that does not mean that both are not present.
I believe that the thrush's song changed the mood because it was a song filled with hope from the divine that inspired him. Darkling Thrush refers to a bird who is weak and fragile, however, even with these qualities, he sacrificed himself.
