In an experiment, a researcher manipulates people's mood by having them listen to "happy" or "depressing" music. he wants to see if mood affects memory performance. after taking the memory test, participants are asked whether or not they liked the music. when he looks at the data he finds that people tended to have better memory after listening to "happy" music. he also finds that participants like the "happy" music more than the "depressing" music. in fact, several participants referred to the "depressing" music as "the worst sound they had ever heard". given this information, which of the following conclusions is the most accurate? a. happy music leads to improved memory because it leads to increased arousal at encoding. b. depressing music not only decreases memory but it sounds bad too. c. happy music leads to improved memory because it puts participants in a better mood. d. no conclusion can be made as the mood manipulation is confounded with music quality.