This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep Disorders, Subject name: Psychiatry
[{'content': 'Cataplexy is characterized by? \nSelect and explain. \nA. Hypnopompic hallucinations, B. Nocturnal penile tumescence, C. Decreased muscle tone, D. Somnambulism', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Decreased muscle tone * Cataplexy is the most common accessory symptom of Narcolepsy and is characterized by sudden decrease in muscle tone, either, local or generalized.", 'role': 'assistant'}]