Question

The greatest source of water in the hydrological cycle is ________.

Answer 1

The correct option is D.
Hydrological cycle refers to the cycle that process the continuous water circulation on the earth surface. Many processes are involved in water cycle, examples are evaporation, condensation, precipitation,transpiration, etc. The constancy of the quantity of water in the hydrological cycle is usually maintained but its distribution changes continuously. The greatest source of water in the hydrological cycle is the ocean. 

Answer 2

I believe the correct answer from the choices listed above is option D. The greatest source of water in the hydrological cycle is the oceans. The oceans accounts for about 96.5 percent of all Earth's water. So, it should contribute more to the amount of water in the water cycle.