When a Liquid Is in Dynamic Equilibrium with Its Vapor

Multiple Choice

When a liquid is in dynamic equilibrium with its vapor at a given temperature,the following conditions could exist:
I.There is no transfer of molecules between liquid and vapor.
II.The vapor pressure has a unique value.
III.The opposing processes, (liquid to vapor) and (vapor to liquid) ,proceed at equal rates.
IV.The concentration of vapor is dependent on time.
Which of the above choices are applicable?

A) I
B) II and III
C) I,II,and III
D) II and IV
E) II,III and IV