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: Radiology
[{'content': 'The facial root of premolar appears to be distal to the lingual root in X-ray. What will be the direction of projection? \nSelect and explain. \nA. Changed vertical direction of projection, B. X-ray projected from distal side, C. X-ray projected from mesial side, D. Changing the tube film distance', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]