If We Find That Two Variables Are Correlated, Which of the Following

If we find that two variables are correlated, which of the following conclusions would be unjustified?

A) we know that changes in one of the variables cause changes in the other
B) we know that we can predict to some extent the value of one variable if we know the value of the other
C) we know that the two variables covary, i.e., change in value together
D) we know that we have quantified a relationship between the two variables