What can be inferred about water?

Câu hỏi: Read the following passage carefully
Our demand for water is constantly increasing. Every year there are more and more people in the world.
Factories turn out more and more products and need more and more water. We live in a world of water. But almost all of it – about 97%-is in the oceans. This water is too salty to be used for drinking, farming, and manufacturing. Only about 3% of the world’s water is fresh. Most of this water is not easily available to man because it is locked in glaciers and icecaps. There is as much water on earth today as there ever was or will ever be. Most of the water we use finds its way to the oceans. There, it is evaporated by the sun. It then falls back to the earth as rain.
Water is used and reused over again. It is never used up. Although the world as a whole has plenty of fresh water, some regions have a water shortage. Rain does not fall evenly over the earth. Some regions are always too dry, and others too wet. A region that usually gets enough rain may suddenly have a serious dry spell and another region may be flooded with too much rain.
Choose an option (A, B, C or D) that best answers each question.
What can be inferred about water?
A. The amount of water on earth is always the same.
B. Water will probably be exhausted.
C. Water can be used once only.
D. Most of the water we use is not rain water.