Swallowing semen or other genital secretions can cure acne

The first step of the scientific method is to test the research question

Indicate whether this statement is true or false.

Randy meets a Californian who grows his own vegetables and refuses to eat nonorganic food. Randy concludes that Californians are overzealous about nutrition. Which critical thinking guideline did Randy overlook?

a. Don't oversimplify b. Tolerate uncertainty c. Avoid emotional reasoning d. Examine the evidence