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: Gynaecology & Obstetrics
[{'content': 'Neonatal alloimmune thrombocytopenia is caused by \nSelect and explain. \nA. B19 parvovirus  infection, B. Maternal - fetal platelet antigen disparity, C. CMV infection, D. Sepsis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Alloimmune thrombocytopenia is caused by maternal fetal platelet antigen disparity.', 'role': 'assistant'}]