In the Shepard and Metzler Study, People Judged Whether Two

In the Shepard and Metzler study, people judged whether two figures that were in different orientations were the same or different. What did this study demonstrate?

A) It takes much longer to rotate pairs in depth (e.g., by turning a figure away from you) than to rotate pairs in the picture plane (e.g., by turning a figure clockwise) .
B) The amount of rotation necessary before making "same-different" judgments influences decision speed.
C) There were no consistent relationships between the variables examined in this study.
D) The propositional-storage interpretation of imagery is correct.