This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
Which of the following is an exception of courvoiser's law 
Select and explain. 
A. Double impaction, B. Poal lymphadenopathy, C. Periampullary Carcinoma, D. None of the above
A: Double impaction
Answer: A: Double impaction 
Explanation: Exceptions to courvoiser's law Double impaction of stones (one in cystic duct and other on CBD) Oriental cholangiohepatitis Pancreatic calculus obstructing the ampulla of vater Mucocele due to Stone in the cystic duct Ref: Sabiston 20th edition Pgno : 1544