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
[{'content': 'Which is the best investigation for carcinoma head of pancreas: \nSelect and explain. \nA. Guided biopsy, B. ERCP, C. Transduodenal/transperitoneal sampling, D. EUS', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Percutaneous liver biopsy under USG or CT guidance can be diagnostic, but there is a risk of hemorrhage as these tumors are highly vascular REF : BAILEY AND LOVE 27TH', 'role': 'assistant'}]