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: Medicine
[{'content': 'A 25 year old man presents with a kidney stone . He is married to his first Cousin and 6 months earlier , his 8 year - old son had a kidney stone as well diagnosis is . \nSelect and explain. \nA. PCKD, B. Medullary Cystic disease, C. Fanconi syndrome, D. Cystinuria', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Cystinuria\xa0 is the most common cause of stones in Childhood.', 'role': 'assistant'}]