This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'New vaginal ring used to prevent pregnancy for an entire year \nSelect and explain. \nA. Segesterone acetate, B. Desogestrel, C. Norgestimate, D. Levonorgestrel', 'role': 'user'}, {'content': 'Answer: A \nExplanation: It is a ring shaped non biodegradable , flexible, white opaque system contain a estrogrn n progesterone ative compounds.', 'role': 'assistant'}]