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': 'The expelled products in ectopic pregnancy originate from : \nSelect and explain. \nA. Decidua basalis, B. Decidua vera, C. Chorionic villi, D. Decidua Capsularis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Decidua vera', 'role': 'assistant'}]