Why Is It Unwise to Conclude That If Two Variables

Why is it unwise to conclude that if two variables are correlated,one must have caused the other?

A) Rarely are only two variables correlated.
B) It is impossible to conclude that two variables are related unless one can measure them perfectly.
C) Variables can never be measured with complete accuracy.
D) Some unmeasured third variable might make them appear related when in fact they are not.
E) Any single variable is bound to have multiple causes.