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': 'Hunter- Schreger bands not present in: \nSelect and explain. \nA. Middle third of enamel., B. Inner third of enamel., C. Outer third of enamel., D. Present all over in enamel.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]