Mediation Has Occurred When

Mediation has occurred when:

A) The relationship between two variables changes as a function of a third variable.
B) The strength of the relationship between a predictor variable and an outcome variable is reduced by including another variable in the model.
C) The strength of the relationship between a predictor variable and an outcome variable is increased by including another variable as a predictor.
D) The relationship between two variables decreases as a function of a third variable.