Water Is Unusual Because It Is Less Dense as a Solid

Water is unusual because it is less dense as a solid than a liquid.This is important for marine organisms because:

A) A layer of ice insulates organisms beneath it.
B) If ice was more dense,the oceans would freeze from the bottom and remain frozen leaving no available space.
C) Cold water holds less oxygen than warm water.
D) All answers are correct.
E) A layer of ice insulates organisms beneath it and If ice was more dense,the oceans would freeze from the bottom and remain frozen leaving no available space only.