an example of a natural - draft system is\na. reverse - cycle (heat pump) refrigeration.\nb. central air…

Brief Explanations:

In hot - water baseboard heating, natural convection (a form of natural - draft) occurs. Hot water in the baseboard heats the surrounding air, which rises due to its lower density, and cooler air moves in to replace it. Reverse - cycle refrigeration, central air - conditioning, and radiant heating do not rely on natural draft in the same way.

Answer:

C. hot water baseboard heating