The Molar Mass of a Solid as Determined by Freezing-Point

Multiple Choice

The molar mass of a solid as determined by freezing-point depression is 10% higher than the true molar mass. Which of the following experimental errors could not account for this discrepancy?

A) Before the solution was prepared, the container was rinsed with solvent and not dried.
B) Some solid was left on the weighing paper.
C) Not all the solid was dissolved.
D) The solid dissociated slightly into two particles when it dissolved.
E) More than the recorded amount of solvent was pipetted into the solution.