This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Surgery
Aminopeptidase is elevated in obstruction of: 
Select and explain. 
A. Ureter, B. Urethra, C. CBD, D. Bladder
C: CBD
Answer: C: CBD 
Explanation: Leucine Aminopeptidase: Increased Leucine aminopeptidase (LAP) activity is seen in: Carcinoma of the pancreas, choledocholithiasis, acute pancreatitis Viral hepatitis. Cirrhosis, carcinoma with liver metastasis In common bile duct obstruction,whether due to carcinoma pancreas or choledocholithiasis, the elevated serum LAP levels returned to normal following relief of the obstruction. This is in agreement with the hypothesis that the increased serum LAP activity in these conditions is the result of bile duct obstrcution Ref: American journal of Gastroenterology Dec1963 Vol. 41 Issue 6, pgno: 620