Which of the Following Is True

Which of the following is true?

A) Changes in personal costs and benefits will exert a predictable influence on the choices of people.
B) If one individual gains from an economic activity, then someone else must lose.
C) If a good is provided free to an individual by government, its production will not consume valuable scarce resources.
D) If the intentions behind a policy are good, you can be assured that the outcome will be desirable.