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: Unknown
The right border of the heart is formed by - 
Select and explain. 
A. Left Ventricle, B. Right Ventricle, C. Right Atrium, D. Left Atrium
C: Right Atrium
Answer: C: Right Atrium 
Explanation: Ans. is 'c' i.e., Right Atrium