Study the phase diagram of a saltwater solution compared to pure water.

Answer
The solute is more volatile when compared to the solvent.
Explanation
From the diagram, the solute is more volatile when compared to the solvent. This is because a volatile solute (i.e., a solute that has a vapor pressure of its own) will contribute to the vapor pressure above a solution in which it is dissolved.
Hence, the correct option is: The solute is more volatile when compared to the solvent.