How are solubility and temperature generally related in a system consisting of a solid solute and a liquid solvent?

Solubility and temperatures are directly related. The higher the temperature of the solvent, the higher the solubility of the solute in the solvent.

Dissolving a solute in a solvent is an endothermic process hence providing heat favors the  process. Higher temperatures cause the molecules of the solvent to have high kinetic energy hence bombard each other and with that of the solute with high frequency. This then ensures fast diffusion of the solute particles in the solvent.

a polar bond is formed when electrons are shared unevenly between atoms

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.