This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Impoant Motor Milestones, Subject name: Pediatrics
[{'content': 'A child can make a bridge with blocks at:- \nSelect and explain. \nA. 2 years, B. 18 months, C. 4 years, D. 5 years', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 4 years - Bridge with blocks 5 years - Gate with blocks', 'role': 'assistant'}]