Read the paragraph from the introduction [paragraphs 1-3]. For this experiment, about 100 participants were asked to answer simple questions about their emotions — whether they felt happy, sad or afraid —and then read a short story out loud. They could hear their own voice through headphones as they were reading. Afterward, they were asked to rate their emotions again using the same questionnaire. Participants were not told that reporting their emotions and reading the story were part of the same experiment. How does the final sentence of the paragraph contribute to the reader's understanding of the study?

A It summarizes the findings of the study by describing participant reactions.

B It reinforces the accuracy of the study by showing participants were objective.

C It demonstrates how researchers were able to solve the primary problem.

D It outlines how emotions were affected by reading the story aloud.