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': 'Dull, boring, gnawing type of pain is due to excitation of: \nSelect and explain. \nA. C fibres., B. A delta fibres., C. Both., D. None.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Dull, boring, gnawing, and excruciating. This kind of painful response is consistent with those resulting from excitation and slower rate of transmission of the "C" nerve fibers in the pulp', 'role': 'assistant'}]