Which statement is true regarding copper's ability to conduct electricity?

copper is a good conductor of electricity because its atoms have a loosely held electron in their outer shell that is able to move freely to other atoms.
copper is a poor conductor of electricity because its atoms are held in positions that cannot move.
copper is a good conductor of electricity because its atoms have electrons that are tightly bound to their shells and will resist movement.
copper is a poor conductor of electricity because it has a free electron in its outer shell that will flow to other copper atoms.