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: Pediatrics
[{'content': "The neonatal kidney achieves concentrating ability equivalent to adult\\'s kidney by – \nSelect and explain. \nA. One year of age, B. Eighteen months of age, C. Three to six months of age, D. Just before puberty", 'role': 'user'}, {'content': 'Answer: A \nExplanation: "Normal adult kidney can produce urine with an osmolality of greater than 1000 m Osm/kg water The healthy newborn infant, subject to water deprivation for 10-14 hours can achieve an osmolality of only 500-700 m Osm /kg. This value increases gradually during the first few months and approximates to the adult value by about one year of age."\nOn the other hand, the newborn can dilute his urine to a minimum of 50 m Osm/kg much like an older child.', 'role': 'assistant'}]