This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
[{'content': 'Minimum vision loss with which cataract - \nSelect and explain. \nA. Blue dot cataract, B. Zonular cataract, C. Anterior polar cataract, D. Posterior polar cataract', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In blue dot cataract, opacities are situated in the peripheral pa of adolescent nucleus and deeper layer of the coex.Opacities are usually stationary and do not affect vision. Zonular cataract is the most common type of congenital cataract presenting with visual impairement. IMG REF', 'role': 'assistant'}]