Heat from burning fuel warms the walls of the firebox section of the furnace in

A. an evaporation system.

B. a compressor compartment.

C. a hot-air heating system.

D. a hot-water heating system.

C. a hot-air heating system.

Explanation:

The warm (or hot) air heating system uses a vent to pull in heat from the outside air and heats it over a gas flame. This warm air circulates via ducts, vents or grills which are located throughout the home. This heating systems are often managed by a thermostat.

So

Heat from burning fuel warms the walls of the firebox section of the furnace in

a hot-air heating system.

Option C is correct