This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Obs), Subject name: Gynaecology & Obstetrics
[{'content': 'Retinal vessels develop by \nSelect and explain. \nA. 4th month, B. 6th month, C. 1st month, D. 3rd month', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (4th month) Ref: yanoff 3rd ed p- 606During development, retinal vessels migrate from the optic disc to the ora serrata beginning at 16 weeks of gestation.Mature vessels develop from these networks and extend to the nasal ora serrata by 36 weeks of gestation and to the temporal ora serrata by 39 - 41 weeks.', 'role': 'assistant'}]