Masahiro Carries on Detailed and Quite Fluent Conversations with Himself

Masahiro carries on detailed and quite fluent conversations with himself in the middle of the night. His wife suspects that he is not really asleep and insists he be tested at the university sleep lab one night. The EEG revealed he was truly asleep while conversing with himself. The brain activity helped the researchers establish ___________________.

A) the correspondence between his mental state and the deep stages of sleep
B) that his conversations were delusional and corresponded to his fatigue levels
C) that when he awoke he could remember what he had said
D) the correspondence between stressful events in his life and his sleep stages