Why Is It That in Cold Winters a Tub of Water

Why is it that in cold winters a tub of water placed in a farmer's canning cellar helps prevent canned food from freezing?

A) As long as the water remains in the liquid phase, evaporation will give off heat to the cellar.
B) If the canned goods are in the tub of water, molecular interactions will keep them from freezing.
C) The cold in the cellar is consumed by freezing the water, not the canned goods.
D) The continual release of energy by the freezing water keeps the temperature of the cellar from going below 0°C.