This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Natural Methods, Barrier Methods, IUDs, OCPs, Subject name: Social & Preventive Medicine
[{'content': 'A woman takes very low dose combined oral contraceptive pills. After how many days of continuously missing to take pills minimum, there is failure of contraceptive method. \nSelect and explain. \nA. One missed pill, B. Two missed pill, C. Three missed pill, D. Four missed pill', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Combined OCPs :- - Contain low doses of estrogen & progesteron. - They contain 0.15 mg of Levo-norgesterol and 0.03 mg of ethinyl estradiol. - With very low dose pills containing 20 mcg of less estrogen, the failure will happen after 2 or more missed pills.', 'role': 'assistant'}]