Oceans cover over 70% of Earth's surface, and precipitation constantly adds freshwater to the oceans. Yet, ocean levels remain relatively constant. Which of the following is the best explanation for why ocean levels remain constant? A. Ocean water is continually changing from a liquid state into a vapor.

B.
Ocean water is continually seeping underground into the ocean floor.

C.
Humans alter the level of the oceans due to our need for drinking water.

D.
It is difficult to change the ocean levels due to the large size of the oceans.