This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Child is 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: Tower of 2 cubes- 15 months Tower of 4 cubes- 18 months Tower of 5-6 cubes- 21 months Tower of 6-7 cubes- 24 months Makes bridge of 3 cubes- 3 years Makes gate of 5 cubes -4 years. Ref: Nelson's 20 th edition- page 75.", 'role': 'assistant'}]