What Determines Equilibrium in a Liquid-Vapor System?

[erisedk]

Homework Statement

A liquid is in equilibrium with its vapor at its boiling point. On an average, the molecules in the two phases have equal:
(A) inter-molecular forces
(B) potential energy
(C) total energy
(D) kinetic energy

Homework Equations

The Attempt at a Solution

I know (A) is wrong as intermolecular forces in liquids are much more than those in gases. However, I'm confused between (B) (C) and (D). I know in gases KE is directly proportional to temperature. I'm not really sure about anything beyond this.

 

[Bystander]

Okay --- it's not KE. That leaves PE and TE; do you think TE might be related more to KE than PE? Or, less?

 

[erisedk]

Why isn't it KE? Shouldn't KE also be proportional to temperature in liquids?
And I don't know whether TE might be more related to KE or PE.