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
Percentage of Gall stones that are radiopaque are 
Select and explain. 
A. 10-20%, B. 30-40%, C. 50-60%, D. 70-80%
A: 10-20%
Answer: A: 10-20% 
Explanation: Ans. (a) 10-20%Ref: Bailey and Love 27th edition Page 1190* Plain X ray will show Radio opaque Gallstones- 10% of patients* Rarely the centre of stone may have Radiolucent Gas in Triradiate or Biradiate Fissure having dark shapes known as "Mercedes Benz Sign or Seagull Sign "* Porcelain Gallbladder is calcified gallbladder.