Which of the following is true?

a.Positive economics deals with how people react to changes in benefits, and normative economics deals with how people react to changes in costs.

b.Positive economic statements are testable, but normative statements are not.

c.Positive economic statements involve value judgments while normative economics focuses on whether a policy will achieve its intended objectives.

d.Positive economic statements focus on policy issues while normative economics focuses on economic theory.