A room contains 25 kg. of air at 100 kPa and $$14^\circ C$$. The room has a 250 W refrigerator and 1 kW electric resistance heater. During a cold winter day, it is observed that both the refrigerator and the heater are running continuously, but the air temperature in the room remains constant. The rate of heat loss from the room during that day is

A

3600 kJ/hr.

B

1250 kJ/hr.

C

4500 kJ/hr.

D

2700 kJ/hr.