The stirring action heated the spoon. Warm air in the room heated the spoon. Heat from the soup was transferred to the spoon. The student's hand transferred heat to the spoon.
I gave my students this multiple choice question: A student heated a pan of soup on a stove. While stirring the soup with a metal spoon, the student noticed the spoon became very warm. What is the most likely reason the spoon became warm?

Only one answer is correct among these 4 choices:
- The stirring action heated the spoon.
- Warm air in the room heated the spoon.
- Heat from the soup was transferred to the spoon.
- The student's hand transferred heat to the spoon.

Could you tell me which one is correct?

Heat from the soup was transferred to the spoon.