A 70-cm-diameter flat black disk is placed at the center of the ceiling of a 1-m × 1-m × 1-m black box. If the temperature of the box is 620°C and the temperature of the disk is 27°C, the rate of heat transfer by radiation between the interior of the box and the disk is
(a) 2 kW

(b) 5 kW

(c) 8 kW

(d) 11 kW

(e) 14 kW