This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Which of the following is not a barrier method ? \nSelect and explain. \nA. Cenntchroman, B. Today, C. Barrier contraceptive, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: <p> Centchroman is not a barrier method of contraception. Centchroman (sagely) is a synthetic non steroidal oral contraceptive. Reference:Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:494. <\\p>', 'role': 'assistant'}]