This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Leukemias and Lymphoma, Subject name: Pediatrics
[{'content': 'Most common gastrointestinal malignancy of childhood is? \nSelect and explain. \nA. Adenocarcinoma, B. Lymphoma, C. Carcinoid, D. Sarcoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ANSWER: (B) LymphomaREF: Atlas of pediatric gastrointestinal disease: Part 1 - Page 87"Lymphoma is the most common malignant tumor of the gastrointestinal tract in children"', 'role': 'assistant'}]