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
On X-ray, right border of the mediastinum is formed by all the following except: 
Select and explain. 
A. Superior vena cava, B. Right atrium, C. Right ventricle, D. Right brachiocephalic vein
C: Right ventricle
Answer: C: Right ventricle 
Explanation: Ans. Right ventricle