ANS:D - all (a), (b) & (c)

The Clausius-Clapeyron equation applies to the vaporization process. The Clausius-Clapeyron equation describes the relationship between the vapor pressure of a substance and its temperature. It is commonly used to understand and predict changes in vapor pressure with temperature during phase transitions, particularly during vaporization (liquid to gas), but it can also be applied to other phase transitions such as sublimation (solid to gas) and melting (solid to liquid). However, it is most frequently utilized in the context of vaporization. Therefore, while the equation can be applied to all of the mentioned processes (sublimation, melting, and vaporization), it is particularly associated with the vaporization process.