Which sentence is punctuated correctly?
a) the veterinarian examined our dog in one room, meanwhile our cat was being examined in a different room.
b) the fire alarm kept ringing for ten minutes finally; the firefighters were able to disconnect the circuit.
c) james wanted to go to new orleans for his vacation, however, he had used up all his vacation days.
d) the temperature plunged down below zero; consequently, our water pipes burst.