C. Character Development, would be my best answer out of the choices you've stated.
Introduction.
A book's introduction is closely related to the content of the book itself. Usually found in nonfiction work, the introduction may summarize the main argument presented in the rest of the book, define any important terms, or fill in background details.
<u>The right answer is</u>
Activists have coined the slogan “toilet to tap” to discourage the use of wastewater.
<u>Explanation</u>
<em>Toilet-to-tap or direct potable reuse is the future of potable water wherever we have acute water shortages but we still have a perception issue to resolve.</em>
They had a lo of minerals