Correlation, variables

What is meant by the statement that two variables are related? Choose the correct answer. ( Two variables are related when a scatterplot can be made of points using the two variables as values, @ Two variables are related when a change in one can be shown to cause a change in the other Two variables are related when a discernible pattern exists between them. @Two variables are related when the value of one can be derived mathematically from the value of the other