This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gall Bladder & Bile Ducts, Subject name: Surgery
Old male with features of jaundice, pale stools, dark urine and mass in the epigastric region. Which of the following diagnosis in unlikely? 
Select and explain. 
A. Pancreatic cancer, B. Biliary cancer, C. Periampullary cancer, D. Chronic cholecystitis
D: Chronic cholecystitis
Answer: D: Chronic cholecystitis 
Explanation: Ans. (d) Chronic cholecystitisRef: Long cases Surgery RRM* From the given details its clear the patient is obeying Courvoisier law- Jaundice + GB palpable.* So he is a case of cancer- Possible options include distal CBD, Periampullary or pancreatic head cancers with Obstruction of CBD