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': 'By what age is the milestone of climbing steps with alternate feet achieved ? \nSelect and explain. \nA. 2 years, B. 3 years, C. 4 years, D. 5 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: O.P. Ghai 7th ed, page 30 A child climbs syairs alternating feet at 30 months. Thus, best answer is 3 years.', 'role': 'assistant'}]