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: Psychiatry
[{'content': 'Stimulation of which of the following nerve causes an elevation in the mood - \nSelect and explain. \nA. Olfactory N, B. Optic N, C. Trigeminal N, D. Vagus N', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Left vagus nerve stimulation is used to elevate the mood in patients with treatment-resistant depression.', 'role': 'assistant'}]