Which excerpt from Thomas Hardy's "The Darkling Thrush" most plainly expresses awe for its subject?

a. "So little cause for carolings/Of such ecstatic sound..." (correct choice)

b. "I leant upon a coppice gate/When Frost was spectre-gray..."

c. "The tangled bine-stems scored the sky,/Like strings of broken lyres..." (incorrect choice)

d. "The land's sharp features seemed to be/The Century's corpse outleant..."

While taking the test, I chose answer C, but the correct answer is A. I would like to know why this is. Can someone please help?