Based on the principles of convection, conduction and thermal radiation, which scenario below is most similar to the following situation?

You put a heating pad on your back after exercising.
A) Feeling a metal wire get warmer as you roast a marshmallow over a fire.
B) Warm air rising in a room where the air is moving.
C) The sun warming up the roof on a house.
D) Cold water sinking in a pot of water being warmed up on the stove.