Researchers Asked Participants to Keep Journals of Their Daily Moods

Researchers asked participants to keep journals of their daily moods and of other variables, such as the weather and how much sleep they got the night before. When asked, many participants reported the amount of sleep the night before was correlated with their moods. When information recorded in the journals was subjected to more systematic statistical analysis, it was found that amount of sleep was not related to participants' self-reported moods. This is most likely because participants __________.

A) relied on causal theories about the relation between mood and sleep
B) underreported the amount of sleep they actually got
C) were distracted when they wrote in their journals
D) were in a bad mood from having to keep the journal