So, first of all let me explain the process of hydration to you.
The water causes the hardening of concrete through a process called hydration. Hydration is a chemical reaction in which the major compounds in cement form chemical bonds with water molecules and become hydrates or hydration products.
Considering this information, the answer is D.
There are various ways, you can recycle or the use of hydroelectricity. Hydroelectricity is energy of water turning turbines or wheels in a dam. There is also air power through windmills. <span />