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: Ophthalmology
[{'content': 'A 28-week baby suffered from respiratory distress syndrome at bih. On day 14 of life, he developed sepsis. No other co-morbidity was seen. He should be evaluated for retinopathy of prematurity at what postnatal age? \nSelect and explain. \nA. 2 weeks, B. 4 weeks, C. 6 weeks, D. 8 weeks', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. 4 weeks', 'role': 'assistant'}]