This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: DNB 2018, Subject name: Pediatrics
[{'content': 'Child able to make tower of 5-6 cubes at which age? \nSelect and explain. \nA. 18 months, B. 24 months, C. 21 months, D. 30 months', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 15 months - Tower of 2 cubes 18 months - Tower of 4 cubes 21 months - Tower of 5-6 cubes 24 months - Tower of 6-7 cubes 3 years - Makes a BRIDGE of3 cubes 4 years - Makes a GATE of 5 cubes', 'role': 'assistant'}]