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 success or failure of direct pulp capping depends on: \nSelect and explain. \nA. Quality and amount of blood flow, B. History of previous pain, C. Age of the patient, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The\xa0 direct\xa0 pulp\xa0 capping\xa0 procedure\xa0 has\xa0 been\xa0 known to be\xa0most\xa0 successful\xa0 in\xa0 younger\xa0 teeth\xa0 where\xa0 a\xa0 mechanical\xa0exposure is\xa0 a\xa0 dry sterile\xa0 field.', 'role': 'assistant'}]