One end of a copper rod is heated. Which statement explains how heat transfer takes place in the copper?
- AEnergetic copper molecules move from the cooler end to the hotter end.
- BEnergetic copper molecules move from the hotter end to the cooler end.
- CEnergetic free electrons move from the cooler end to the hotter end.
- DEnergetic free electrons move from the hotter end to the cooler end.