Recall that there is a theory that chocolate spread on the wings of an airplane improves its air dynamic properties. Dr. Z ran a regression on thickness of chocolate layer on the wing vs. craft characteristics and got an R² of -1. What does that mean?

A) The thicker the layer, the better for the aircraft.
B) She can reject the null hypothesis.
C) Not enough information.
D) She made a calculation error because R² by definition cannot be less than 0.
E) The thicker the chocolate layer, the worse for the aircraft.