Participation in long-term exercise programs usually result in:
Group of answer choices
a. a statistically significant reduction in depression in all exercisers, no matter what their levels of depression were before the exercise program began.
b. a statistically significant reduction in depression in exercisers who had elevated scores in depressed before exercising.
c. a statistically significant reduction in depression and extroversion.
d. a statistically significant reduction in both non-depressed and depressed exercisers, but greater reductions for the depressed exercisers.