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 mean setting time of MTA is: \nSelect and explain. \nA. 135 ± 5 min, B. 145 ± 5 min, C. 155 ± 5 min, D. 165 ± 5 min', 'role': 'user'}, {'content': "Answer: D \nExplanation: The setting time for MTA is lengthy, about 165 minutes for the initial set and less than 6 hours for the final set, which is a major drawback of\xa0using this cement.\nPhillip's science of dental material 12th edition page 332", 'role': 'assistant'}]