Fact 1: If a thermal conductor is exposed to a source of heat then that conductor may become hot.

Fact 2: Copper is a great thermal conductor.

Given the two facts above, answer the question "If what is exposed to a source of heat then that conductor may become hot?" with the following options: 
- Energy.
 - heat sources
 - energy
 - coal
 - an object
 - copper
 - plastic
 - thermometers


 

      copper   