The birds sit silently and stare. Which revision below includes a prepositional phrase?
A. The birds sit silently and stare, unmoving and unblinking.
B. The big, black birds sit silently and stare.
C. The birds sit silently and stare, and he backs away slowly.
D. Since he saw that movie, he gets nervous whenever the birds sit silently on the roof and stare at him.