This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
The 'beading' appearance is seen in the condition: 
Select and explain. 
A. Chronic pancreatitis, B. Acute pancreatitis, C. Gall stone ileus, D. Sub-acute intestinal obstruction
A: Chronic pancreatitis
Answer: A: Chronic pancreatitis 
Explanation: In chronic pancreatitis, the pancreatic duct may show beading or a chain-of-lakes or string-of-pearls appearance because of alternating stenosis and dilatation of the pancreatic duct. Other features of chronic pancreatitis include strictures, cysts and ductal calculi.