This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Childhood malignancies, Subject name: Pediatrics
[{'content': "A 2-year-old male child presents with a lump in the right side of the abdomen. Ultrasound revealed it to be a solid mass. On examination, his right arm and leg were found to be longer. The most likely diagnosis is: \nSelect and explain. \nA. Wilms' tumor, B. Neuroblastoma, C. Angiomyolipoma, D. Nephroblastoma", 'role': 'user'}, {'content': 'Answer: A \nExplanation: The finding of right arm and leg to be longer suggests hemihyperophy. This is a feature of Beckwith Wiedemann syndrome associated with Wilms tumor.', 'role': 'assistant'}]