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': "During root canal instrumentation, the apical constriction is violated and enlarged to a size no. 50 instrument, which of the following is appropriate treatment for this canal: \nSelect and explain. \nA. Obturate with gutta-percha and surgically remove extruded excess, B. Fit a No.50 gutta-percha cone with sealer and carefully condense, C. Fit a No.50 gutta-percha cone with sealer but don't condense so as to keep the G.P. from being pushed into the foramen, D. Reinstrument 1 mm short of the foramen to a size No.60 or larger and obturate using an appropriately sized master cone", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]