What Is the Outside Temperature If 4000 Kcal of Heat

What is the outside temperature if 4000 kcal of heat is lost through a 4.0 m² pane of 0.30 cm thick glass (k = 2.0 × 10^-4 kcal/s∙m∙°C) in one hour from a house kept at 20°C?

A) 0°C
B) 4°C
C) 16°C
D) 18°C
E) 24°C