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
All the following are radiological features of mitral stenosis except: 
Select and explain. 
A. Straight left hea border, B. Oligaemia of the upper lung fields, C. Pulmonary haemosiderosis, D. Lifting of the left bronchus
B: Oligaemia of the upper lung fields
Answer: B: Oligaemia of the upper lung fields 
Explanation: Ans. Oligaemia of the upper lung fields