Some Scientists Assert That There Would Be No Life on Earth

Some scientists assert that there would be no life on earth if ice did not have a molecular structure with a lot of open space because

A) ice would be so light that it could never form, leaving too much water on the Earth's surface.
B) ice would be less dense than it is now and float too much
C) ice would be denser than water and having a solid sink in its own liquid form would violate the conservation of energy.
D) the density of ice would be greater than water and lakes would freeze solid - from the bottom up.