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: Dental
[{'content': 'Patient having tooth fracture without involving pulp\nhaving sensitivity is due to \nSelect and explain. \nA. Fluid flow in dentinal tubules, B. Stimulation of nerve ending, C. Due to extensive pressure created by occlusal contacts, D. Due to change in intrapulpal pressure', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]