This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Which of these is an FDA approved indication for use of modafinil as an adjunct ? \nSelect and explain. \nA. Major depression and associated lethargy, B. Narcolepsy, C. Obstructive sleep apnea, D. Shift work disorder', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]