Read the sentences from the sections "Changing The Tone Of Your Voice" and "Hearing Tone Of Your Voice Can Alter Your Mood." What participants didn't know is that the pitch of the voice they were hearing in their headphones was actually slightly modified. Instead, the participants in this study ended up changing their feelings to match what they had heard. The two sentences develop the significance of the study by

A outlining a cause and an effect of the tone the participants heard.

B describing a problem participants encountered and a solution.

C presenting a contrast between what scientists expected and learned.

D illustrating how the results participants felt changed over time.