This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bile duct, Subject name: Surgery
Non-resectability criteria in hilar cholangiocarcinoma are all except: 
Select and explain. 
A. Involvement of secondary biliary radicals bilaterally, B. Metastasis to celiac nodes, C. Involvement of right branch of poal vein, D. Contralateral involvement of bile duct
C: Involvement of right branch of poal vein
Answer: C: Involvement of right branch of poal vein 
Explanation: Criteria of Un-resectability in Hilar Cholangiocarcinoma:- 1. Hepatic duct involvement up to secondary radicals bilaterally 2. Encasement or occlusion of the main poal vein proximal to its bifurcation 3. Atrophy of one lobe with encasement of contralateral poal vein branch 4. Atrophy of one lobe with contralateral involvement of secondary biliary radicals 5. Histologically proven metastasis to N2 lymph nodes 6. Liver, lung or peritoneal metastasis