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': 'According to weins modification of the working length determination if bone resorption is there then: \nSelect and explain. \nA. Reduce the length by 0.5mm, B. Reduce the length by 1mm, C. Reduce the length by 1.5mm., D. Reduce the length by 2mm.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Wein modification of working length determination by radiograph:\xa0\n1. Reduce length by 1 mm if NO root + bone resorption\xa0\n2. Reduce length by 1.5 mm if bone resorption\xa0\n3. Reduce length by 2 mm if both root and bone resorption', 'role': 'assistant'}]