In the Featured Study on the Relationship Between Depression and Heart

In the Featured Study on the relationship between depression and heart disease, what evidence did the authors use to support their assertion that depression increases the risk of heart disease, rather than suggesting that it is heart disease that causes depression?

A) Depression was a stronger predictor of mortality than was heart disease.
B) In many cases, depression preceded development of heart disease.
C) Depression was associated with greater mortality only among those without pre-existing heart problems.
D) Symptoms of depression were found only in people who did not have heart disease.