It Is Late at Night, and David Is Studying for an Exam.David

Multiple Choice

It is late at night, and David is studying for an exam.David looks up and sees his older brother Jeff standing in his doorway.David speaks to him but gets no response.Jeff's eyes are open but he has a blank expression on his face, and Jeff shuffles his feet rather than walking normally.David follows him back to his room, and Jeff gets back into bed.David has just witnessed an episode of

A) narcolepsy.
B) somnambulism.
C) REM sleep behavior disorder.
D) night terrors.