Mark Is a Middle-Aged Man Who Has Recently Begun to Talk

Multiple Choice

Mark is a middle-aged man who has recently begun to talk and flail about while he is sleeping,which is very aggravating to his wife.It seems as if he is acting out a dream.Which sleep disorder is most similar to Mark's problem

A)  REM sleep behaviour disorder 
B)  sleep apnea 
C)  somnambulism 
D)  night terrors