A furnace chimney is made of 14 cm thick brick with a heat transmission coefficient of 1.4 W/mK. Find the outer surface temperature of the chimney, given that the outer surface of the chimney radiation absorption coefficient is 0.79, the flue gas temperature is 300 °C, the external ambient temperature is 27 °C, and the external heat transfer coefficient is 17 W/m²K.

a) 125 °C

b) 140 °C

c) 420 K

d) 350 K

e) 380 K