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 defect in matrix formation during formation of enamel leads to \nSelect and explain. \nA. Gnarled enamel, B. Enamel tufts, C. Enamel hypoplasia, D. Mamelons', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]