The total amount of water on earth remains the same.
Option: A
Step-by-step explanation:
The quantity of water on Earth remains the same now as it was in the Olden days. All water which is consumed by living things continue to be as part of the Earth's total water content.
The total amount is not exactly constant, as there are two fluxes of water between Earth and the rest of the solar system. There is a steady rain of water-bearing meteoroids hitting the planet, which slowly increases the amount of water. At the same time, molecules of water often dissociate in the upper atmosphere into hydrogen and oxygen due to ultraviolet light from the sun. Some of the hydrogen atoms have enough energy to escape from Earth’s gravitational field, and so are lost. This slowly decreases the amount of water. In addition, tectonic plate subduction is constantly carrying water down into Earth’s mantle, and volcanoes are constantly spewing water out onto the surface again. The balance between the two processes can change considerably over time. But all of these actions are meager compared to the total quantity of water on our planet, and two of them are in the opposite direction of the other two. So the overall change is insignificant, even when considered over long spans of geologic time.