In energy economics, "BTU" stands for

A) boiling temperature unit.
B) base tax utility.
C) British thermal unit.
D) base technology utility.

BTU

British Thermal Unit, a measure of heat energy used in the power, steam generation, heating, and air conditioning industries.

British Thermal Unit

A measure of heat energy defined as the amount needed to raise the temperature of one pound of water by one degree Fahrenheit.