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: Radiology
Widening of C-loop of duodenum/broad loop of duodenum on X-ray is diagnostic of: 
Select and explain. 
A. Chronic pancreatitis, B. Carcinoma head of pancreas, C. Periampullary carcinoma, D. Calculi in ampulla of vater
B: Carcinoma head of pancreas
Answer: B: Carcinoma head of pancreas 
Explanation: Ans. Carcinoma head of pancreas