A Copper Sheet of Area Is Bonded to an Aluminum

A copper sheet of area is bonded to an aluminum sheet of area and thickness 1.00 mm.The outside surface of the copper sheet is held at a temperature of 80 ^$\circ$ C and the aluminum sheet at 40 ^$\circ$ C.The temperature of the copper-aluminum interface is 52 ^$\circ$ C.What is the thickness of the copper sheet?

A) 2.8 mm
B) 3.6 mm
C) 4.1 mm
D) 5.2 mm
E) 6.3 mm