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
Which of the following will cause posterior impression on barium swallow: 
Select and explain. 
A. ASD, B. VSD, C. Aberrant right subclavian artery, D. Pulmonary vascular hypertension
C: Aberrant right subclavian artery
Answer: C: Aberrant right subclavian artery 
Explanation: Aberrant right subclavian artery produces the classical appearance of a posterior impression on the proximal esophagus and left sided aortic arch impression.