Fast food restaurants keep food hot with infrared lamps. the heat is transferred to the food by a. condensation c. convection b. conduction d. radiation

There are three modes of heat transfer, conduction, which occurs in non-flowing media, convection, which occurs in flowing media, and radiation, which occurs via electromagnetic waves. Infrared radiation is a type of electromagnetic wave, possessing lower frequency than visible light, and it is the means through which radiation heat transfer occurs. The answer is D. radiation.

Fast food restaurants keep food hot with infrared lamps. The heat is transferred to the food by d. radiation.
There is convection in between the heat source, but the heat is still radiated.
Radiation is the transfer of pure energy, unlike convection and conduction which are basically molecule to molecule contact.