This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nerve Physiology, Subject name: Physiology
[{'content': 'Which of the following types of nerve fibers carry pain - \nSelect and explain. \nA. A- alpha, B. A-beta, C. A- gamma, D. A-delta', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans- D.', 'role': 'assistant'}]