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
Normal hilar shadow in X-ray chest is produced by all except - 
Select and explain. 
A. Pulmonary artery, B. Bronchus, C. Lower lobe viens, D. Upper lobe veins
C: Lower lobe viens
Answer: C: Lower lobe viens 
Explanation: "The lower lobe veins do not cross the hill and, therefore, do not contribute to hilar shadow".

Hilar shadow is formed by pulmonary arteries (predominant), upper lobe pulmonary veins (2nd major). Lobar bronchi, bronchopulmonary lymph nodes and a small amount of fat contribute little to the overall hilar shadow.