Consider the following statements pertaining to the Clapeyron equation:
1. It is useful to estimate properties like enthalpy from other measurable properties.
2. At a change of phase, it can be used to find the latent heat at a given pressure.
3. It is derived from the relationship
$\left ( \frac{\partial p}{\partial V} \right )_{T} = \left ( \frac{\partial S}{\partial T} \right )_{V}$
Which of the statements given above are correct?
a. 1, 2 and 3 b. Only 1 and 2
c. Only 1 and 3 d. Only 2 and 3