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': 'High rate of failure after direct pulp capping in primary\nteeth is due to \nSelect and explain. \nA. Law vascularity of pulp, B. High cellular content of pulp, C. Large number of unmyelinated nerves, D. Narrow ribbon shaped root canals', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]