This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pneumoconiosis, Subject name: Medicine
[{'content': 'Mesothelioma is most commonly caused by? \nSelect and explain. \nA. Asbestosis, B. Silicosis, C. Anthracosis, D. Coal workers pneumoconiosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) AsbestosisRef: Harrison 19th ed. /1689* Working with asbestos is the most common risk factor for mesothelioma.* Indeed, the relationship between asbestos and mesothelioma is so strong that many consider mesothelioma a "signal" or "sentinel" tumor.* In rare cases, mesothelioma has also been associated with irradiation of the chest or abdomen, intrapleural thorium dioxide (thorotrast) as a contrast medium, and inhalation of other fibrous silicates, such as erionite.', 'role': 'assistant'}]