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: Forensic Medicine
[{'content': 'A patient presents with a history of continuous headache for the past 8 years. Repeated examinations had failed to reveal any lesion. The patient is convinced that he has a tumor in his brain. The diagnosis is: NIMHANS 08 \nSelect and explain. \nA. Hypochondriasis, B. Somatization, C. Somatoform pain disorder, D. Obsessive Compulsive Disorder', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Hypochondriasis', 'role': 'assistant'}]