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: Medicine
[{'content': 'A man presented with bilateral crepitations in the base of the lungs and signs of pneumonitis with a history of exposure to pigeon feces. Which of the following is true about this condition? \nSelect and explain. \nA. Diagnosis can be made on the basis of history, B. CT scan is investigation of choice, C. Chest X-ray will reveal characteristic changes, D. It is type I hypersensitivity reaction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. Diagnosis can be made on the basis of history', 'role': 'assistant'}]