Definition: You are given a question on high school chemistry. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: The relationship between the vapor pressure of a liquid and the heat of vaporization is expressed in the
(A)Rydberg equation (B)Gibbs free energy equation (C)Clausius-Clapeyron equation (D)Arrhenius equation

C