A Theory Suggests That X Should Have a Positive Effect

Multiple Choice

A theory suggests that X should have a positive effect on Y. Upon analyzing a set of data, the correlation between X and Y is 0.55, and remains just as strong when Z is controlled. What does this tell us about the theory in question?

A) The theory was on the right track, but had the direction of the effect reversed.
B) The theory is proven correct.
C) The theory is supported, but other control variables need to be considered.
D) Nothing can be learned about the theory.