Answer:
Option A
Step-by-step explanation:
The answer is option A or "Feeling a metal wire get warmer as you roast a marshmallow over a fire." The example given is a clear example of conduction because its the transfer of the heat from the heating pad to your back after you finish exercising, in option A it is also conduction because its the transfer of heat from the fire to the metal wire you are roasting a marshmallow. The answer isn't option B or option D because these are both convection where warm air rises and cold air sinks. Also the answer isn't option C because this is a example of thermal radiation, which is when the radiation from the sun is increasing the temperature on the roof of the house.
Hope this helps.