ANS:B - remain unchanged.

The correct statement is: The evaporation of an aqueous solution of sugar causes its molarity to increase. When an aqueous solution of sugar evaporates, the water component of the solution evaporates, leaving behind a more concentrated solution. As a result, the amount of solute (sugar) remains the same while the volume of the solution decreases. Since molarity is defined as the moles of solute per liter of solution, when the volume of the solution decreases while the amount of solute remains constant, the molarity of the solution increases. Therefore, the evaporation of an aqueous solution of sugar causes its molarity to increase.