The reaction 2 cu + o2 → 2 cuo has long been called an oxidation-reaction. copper also reacts with chlorine:

cu + cl2 → cucl2. in such a reaction:

a. copper is also oxidized even though no oxygen is present.
b. chlorine is oxidized.
c. oxidation occurs, but reduction does not.
d. there is no change in oxidation numbers.

well in order to answer this question you have to provide more information < 3

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.