Read the excerpt from "Healthy Eating." But no one can ignore the damage being wrought by all this bad eating. More than one out of three adults in the United States -- 37.5 percent -- are obese, according to the Centers for Disease Control and Prevention. Some of the leading causes of death -- heart disease, stroke and type 2 diabetes -- are directly linked to obesity. And childhood obesity has tripled in the last 30 years. With more than a third of kids between 6 and 19 considered obese, the CDC reports, they are at substantially more risk for developing cardiovascular disease, diabetes, bone and joint conditions, and cancer.

The author's argument that a poor diet can be harmful to a person's health is

A. ineffective, because it lacks clear and reasonable evidence.
B. ineffective, because it leaves the reader with questions.
C. effective, because it addresses and refutes a counterclaim.
D. effective, because it includes facts from a credible source.