In this article, the authors write "Consider a hypothetical example. A chief executive is concerned that her employees are taking insufficient advantage of the company's policy of matching contributions to retirement savings accounts. She suspects that telling her workers how many others their age are making the maximum contribution would nudge them to save more, so she includes this information in personalized letters to them.

If contributions go up, maybe the new policy worked. But perhaps contributions would have gone up anyhow (say, because of an improving economy). If contributions go down, it might be because the policy failed. Or perhaps a declining economy is to blame, and contributions would have gone down even more without the letter."

The scenario described best represents an example of a study with findings that would have:

(Hint: Explore Figures 2.28 and 2.29 and the relevant text around those figures.)

a.high internal validity.

b.poor construct validity.

c.high construct validity.

d.poor internal validity.