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': 'The non-active carious lesion is distinguished by all except: \nSelect and explain. \nA. Covered by a layer of plaque, B. Soft and leathery in consistensy, C. Brown or black discolouration, D. Severe pain during caries removal', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]