B: The emergency <em>lights</em> atop the fire trucks <em>were</em> flashing. Lights is your noun and were acts like your verb.
for A it should be: The exhibits on the lower level are not currently open to the public.
for C it should be: That man, wearing sunglasses, seems to be an undercover police officer.
for D it should be: Perry, like his younger sister Pauline, writes very neatly.
Hopefully this helped and good luck.
I think compound because there were no dependent/independent clauses.
