A statement is made about correlation. State whether the correlation is positive or negative and whether the correlation is most likely due to coincidence, a common underlying cause, or a direct cause.

As Thomas's income rose over the last 20 years so has his stress level.
Select one:

A.
Positive correlation; direct cause

B.
Negative correlation; common underlying cause

C.
Positive correlation; common underlying cause

D.
Positive correlation; coincidence