When water in a lake freezes, the ice that forms floats on top of any water that

When water in a lake freezes, the ice that forms floats on top of any water that is still liquid. Why does the ice float? A. Ice is less dense than liquid water, so it floats.
B. Air bubbles trapped in the ice cause the ice to float.
C. Ice crystals are polar, and they float on top of non-polar water.
D. The ice forms at the top of the water, so it stays there and floats.