before 11 9 this is needed before

If i understand your question right, then your atomic number & number of protons  is below the name so 6. Your atomic mass is at the bottom. Your number of electrons will be the sum of whatever your protons and neutrons are

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.