The answer is the first one, you must always cite your sources, even if you have not directly quoted them. It also adds credibility to your work (this is not the only reason, it is merely an incentive)
Answer: a.) is the point.
a. People should drink tap water rather than bottled water.
Explanation:
The other statements are support for that point.
<h2><em>Eiztari</em></h2>
C. a wise person tries to anticipate opportunity
