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: Radiology
[{'content': 'Periventricular calcification is often due to: \nSelect and explain. \nA. Toxoplasmosis, B. Cytomegalic infection, C. Congenital syphilis, D. All of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Cytomegalovirus', 'role': 'assistant'}]