You have two charges as shown in the image: A (which is positively charged) and B (which is negatively charged). If you insert a positive charge C in the middle of A and B, how would A and B move.
B
A
+
Оа
Oь
Ос
Od
A and B would move toward C.
A would move toward C, and B would move away from C.
A and B would move away from C.
A would move away from C and B would move toward C.

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.

you need to have a picture of the atom that way we can answer it