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': 'Buccolingual positioning of mandibular Canal can be assessed by: \nSelect and explain. \nA. Horizontal 0 and -20 degree., B. Horizontal 0 and -15 degree., C. Vertical 0 and -20 degree., D. Vertical 0 and -15 degree.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: “Periapical radiographs taken from two vertical angulations, 0° (parallel technique) and – (Minus) 20°, determine the buccolingual position of the canal”.\n“Periapical radiographs taken from two Horizontal angulations, 0° (parallel technique) and – (Minus) 20°, may differentiate between buccal and lingual roots”.', 'role': 'assistant'}]