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
On radiography widened duodenal 'C' loop with irregular mucosal pattern on upper gastrointestinal barium series is most likely due to: 
Select and explain. 
A. Chronic pancreatitis, B. Carcinoma head of pancreas, C. Duodenal ulcer, D. Duodenal ileus
B: Carcinoma head of pancreas
Answer: B: Carcinoma head of pancreas 
Explanation: Ans. Carcinoma head of pancreas