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
All are true about pigmented stones except: 
Select and explain. 
A. Seen in cholangiohepatitis, B. Secondary CBD stones, C. Primary CBD stones, D. More common in Asians
B: Secondary CBD stones
Answer: B: Secondary CBD stones 
Explanation: Ans. (b) Secondary CBD stonesRef: Sabiston 19/e p 1485-1486* Black pigmented stones are seen in hemolytic states.* Brown pigmented stones can form in the bile duct itself (Primary Bile duct stone)* MC stone in Asian People* Hepato lithiasis - the commonest stone is Earthy Brown Stones