This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Physiology of Pain, Subject name: Physiology
[{'content': 'Which of the following is an impoant functional parameter of pain receptors? \nSelect and explain. \nA. Exhibit little or no adaptation, B. Not affected by muscle tension, C. Signal only flexion at joint capsules, D. Can voluntarily be inhibited', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Pain receptors exhibit little or no functional adaptation. Its impoance is that it allows the pain to keep the person apprised of a tissue-damaging stimulus as long as it persists.', 'role': 'assistant'}]