Bodies of Fresh Water Undergo a Process Called Turnover, Which

Bodies of fresh water undergo a process called turnover, which typically happens in the spring and in the fall.Which of the following best explains this phenomenon?

A) Water is most dense at 4 degrees Celsius, a temperature it reaches on the surface in the spring and in the fall, and it sinks to the bottom.
B) When ice forms or melts, it causes currents to flow laterally, stirring up the water in the entire body.
C) Ice forms and sinks to the bottom because it is heavier than water; this pushes bottom water upward.