B: The emergency lights atop the fire trucks were 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.