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: Surgery
[{'content': 'Stress ulcers is caused by all of the following except? \nSelect and explain. \nA. Bums, B. Cortisol therapy, C. Penicillin therapy, D. Pulmonary insufficiency', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]