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
Earliest sign of pulmonary venus hypeension on chest radiograph is: 
Select and explain. 
A. Pleural effusion, B. Kerley B lines, C. Cephalization of veins, D. Kerley a lines
C: Cephalization of veins
Answer: C: Cephalization of veins 
Explanation: Ans. Cephalization of veins