Answer: option B. Increase Increase decreasing
Analysis:
Both reduction of freezing point and reduction of vapor pressure of solutions are colligative properties. Other colligative properties are increase of boiling point and increase of osmotic pressure.
Colligative properties are those physical properties that depends on the number of particles of solute dissolved in the solvent.
When the number of particles increase, molarity and molality (two measures of concentration) increase.
Regarding the vapor pressure, the theory afirms that the greater the number of particles of solute in a solvent, the lower the vapor pressure of the resultant solution, which means that the vapor pressure will increase with increasing the molarity (or molality) and is is equivalent to the statement "the vapor pressure will increase with decreasing the molarity of a nonvolatile solute".
With respect the freezing point, the theory is that the depression on the freezing point is proportional to the number of particles of solute dissolved, which implies the statement "the freezing point of a solution will increase with decreasing the molarity of a nonvolatile solute".
