According to the Meta-Analysis by Kvam and Colleagues (2016), How

According to the meta-analysis by Kvam and colleagues (2016) , how successful is exercise as a therapeutic treatment for unipolar depression?

A) Exercise is only effective when combined with antidepressant medication
B) Exercise is more effective than antidepressant medication
C) Exercise is only effective in the absence of antidepressant medication
D) Exercise is more effective than no treatment or standard care and appears promising as an adjunct to antidepressant medication