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: Pathology
[{'content': 'Pain due to acute irreversible pulpitis is: \nSelect and explain. \nA. Spontaneous, B. Sharp-shock like, C. Lasting for short time, D. Continuous', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]