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': 'A patient is having Mitral stenosis. His x-ray will show all of the following finding except \nSelect and explain. \nA. Lifting up of left bronchus, B. Double atrial shadow, C. Obliteration of retrosternal shadow on lateral x-rays, D. Posterior displacement of esophagus on barium swallow', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Obliteration of retrosternal shadow on lateral X Ray', 'role': 'assistant'}]