This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gallstone Disease, Subject name: Surgery
Radio-opaque gall stones - 
Select and explain. 
A. 10%, B. 20%, C. 30%, D. 40%
A: 10%
Answer: A: 10% 
Explanation: Ans. is 'a' i.e., 10% o Only about 15% gallstones contain enough calcium to render them radioopaque,o Calcium bilirubinate if present in significant amount in gallstones makes them radioopaque,