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': 'In a child, one should be worried if- \nSelect and explain. \nA. Stammering occurs at 3 years, B. Lack of Toilet control at 2.5 years, C. Teeth do not erupt by 11 months, D. Social smile absent by 10 weeks', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Social smile absent by 10 weeks o Social smile develops by 2 months About other options o Delayed eruption is usually considered when there are no teeth by approximately 13 months of age --- Nelson o Toilet control develops by 3 years when child can withhold and postpone his bowel movement --- O.P. Ghai o Stammering may occur at 3 years --- Neeraj Ahuja", 'role': 'assistant'}]