Conduction of Heat: a Heat Conducting Rod, 1

Conduction of heat: A heat conducting rod, 1.40 m long, is made of an aluminum section that is 0.50 m long and a copper section that is long. Both sections have cross-sectional areas of The aluminum end and the copper end are maintained at temperatures of and respectively. The thermal conductivity of aluminum is 205 W/m ∙ K of copper is 385 W/m ∙ K. The rate at which heat is conducted in the rod is closest to

A) 20 W.
B) 18 W.
C) 23 W.
D) 25 W.
E) 28 W.