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': 'Pioneer nerve fibers enter into dental papilla in \nSelect and explain. \nA. Bud stage, B. Cap stage, C. Advanced bell stage, D. Bell stage', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]