Which solid conducts electricity most efficiently?
potassium chloride
sugar
graphite
silver

Option (c) is the correct answer.

Explanation:

Graphite is an allotrope of carbon atom. Also, being a solid it is able to conduct electricity due to the presence of free or mobile electrons.

Whereas in solid form potassium chloride, sugar and silver cannot conduct electricity as there are no free electrons present.  

Thus, we can conclude that out of the given options, graphite is the solid which conducts electricity most efficiently.

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.

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.