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
A patient is having mitral stenosis. His X-ray will show all of the following findings except – 
Select and explain. 
A. 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
C: Obliteration of retrosternal shadow on lateral X-rays
Answer: C: Obliteration of retrosternal shadow on lateral X-rays 
Explanation: Radiological signs of mitral stenosis

Due to left atrial enlargement:- Straightening of left heart border, elevation of left main bronchus with the widening of the carina, double atrial shadow (Double density sign), posterior displacement of the esophagus on barium swallow, Prominent posterosuperior part of the cardiac shadow.
Due to pulmonary venous hypertension :- Diversion of blood flow from the lung bases to the upper zone (cephalization of pulmonary vascularity), pulmonary hemosiderosis, peribronchial cuffing, Kerley B lines and sometimes Kerley 'A' lines, perihilar haze, alveolar edema, small pleural effusion, pulmonary ossicles, fine punctate calcification in lung.
Due to elevated pulmonary hypertension:- Enlargement of central pulmonary vessels with peripheral pruning.