A Correlational Relationship Between Any Two Variables (A and

A correlational relationship between any two variables (A and

A) C causes common variation in both A and B, hence the observed correlation between A and
B) C may mediate the relationship between A and B, such that A leads to changes in C, and C then leads to changes in
C) C and A are measures of the same underlying construct, with different sources of error, such that when C is included in a multiple regression, the relationship between A and B disappears.
D) A and B are, in fact, unrelated were we able to objectively measure this relationship in reality, so the observed correlation between A and B is due to a third variable: measurement error.