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': "A 35 years old male, with pre-morbid anxious traits & heavy smoker, believes that he has been suffering from 'lung carcinoma' for a year, No significant clinical finding is detected on examination and relevant investigation. He continues to stick to his belief despite evidence to the contrary. In the process, he has spent a huge amount of money, time and energy in getting himself unduly investigated. He is most likely suffering from - \nSelect and explain. \nA. Carcinoma lung, B. Hypochondriacal disorder, C. Delusional disorder, D. Malingering", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Preoccupation with fear of serious illness (lung cancer), normal clinical examination & investigation and multiple investigations suggest the diagnosis of hypochondriasis.', 'role': 'assistant'}]