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': 'In a lateral cephalogram, the distance at which the film is placed from the mid-sagittal plane is: \nSelect and explain. \nA. 10 cms, B. 12 cms, C. 15 cms, D. 18 cms', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]