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': 'Rubella cataract is seen as - \nSelect and explain. \nA. Posterior polar cataract, B. Nuclear cataract, C. Blue dot cataract in young, D. Cuneiform cataract', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A progressive type of congenital cataract, originally nuclear, is assosiated with occurrence of rubella in the mother if the infection is contracted in the 2nd and sometimes in 3rd month if pregnancy.', 'role': 'assistant'}]