Unlike Fresh Water, Ocean Water Contracts as It Is Cooled

Unlike fresh water, ocean water contracts as it is cooled all the way down to its freezing point, which is about -18°C. Why?

A) As the water cools, it becomes more dense and then it sinks. The pressure from the weight of the ocean exerted on the ice below the surface of water causes it to be more dense.
B) macrocrystals instead of microcrystals are formed during the freezing of ocean water.
C) As the water cools, the salt ions in the ocean water pull the molecules closer together.
D) The presence of a solute disrupts the rate of ice microcrystal formation.