This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
[{'content': "In Meckel's diverticulum, ectopic gastric tissue is diagnosed by: \nSelect and explain. \nA. Radionucleotide scan, B. Endoscopy, C. Ultrasound, D. RBC tagged scanning", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a', 'role': 'assistant'}]