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 person with mitral stenosis has the following radiological signs except 
Select and explain. 
A. Straightening of left heart border, B. Double density sign, C. Elevation of Right main bronchus, D. Kerley B lines
C: Elevation of Right main bronchus
Answer: C: Elevation of Right main bronchus 
Explanation: Elevation of left main bronchus with widening of Carina - Mitral stenosis