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': 'Cervical bulge. True is \nSelect and explain. \nA. Enamel rods at cervical region directed occlusally, B. Results in constriction at cervical region, C. Is characteristic of deciduous teeth, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]