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: Surgery
Commonest cause of pyogenic liver abscess - 
Select and explain. 
A. Biliary Sepsis., B. Biliary Colic, C. Appendicitis, D. Sigmoid Diverticulitis
A: Biliary Sepsis.
Answer: A: Biliary Sepsis. 
Explanation: None