A solute depresses the freezing point because the solute . a. is colder than the solvent

b. disrupts crystal formation of the solvent

c. tends to sink to the bottom of the solution

d. has bigger molecules than the solvent

The correct option is b: A solute depresses the freezing point because the solute disrupts the crystal formation of the solvent.

Explanation:

The depression of the solvent's freezing point is caused by the addition of a solute because the presence of the molecules of the solute interferes in the arrange and close up of the molecules of the solvent to form the crystal of the solid.

The attraction of the solute molecules to the solvent molecules interfere with the formation of the solid, so the solution must be cooled to a lower temperature so it can form the solid.

Hence, the correct option is b: A solute depresses the freezing point because the solute disrupts the crystal formation of the solvent. The other options are incorrect.

I hope it helps you!