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 do not contribute to hilar shadow 
Select and explain. 
A. Pulmonary arteries, B. Upper lobe pulmonary veins, C. Lower lobe pulmonary veins, D. Lobar bronchi
C: Lower lobe pulmonary veins
Answer: C: Lower lobe pulmonary veins 
Explanation: Lower lobe veins do not cross the hila and therefore do not contribute to hilar shadow.