This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demography and Family Planning, Subject name: Social & Preventive Medicine
[{'content': 'Which of the following Natural method of contraception is most effective? \nSelect and explain. \nA. Calendar method, B. Billing method, C. Symptothermic method, D. Basal body temperature method', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. c (Symptothermic method) (Ref. Park's textbook of PSM 22nd/403, 404)CONTRACEPTIVE METHODS# SPACING : Barrier methods, -Intrauterine devices, -Hormonal, -Postconceptional, Miscellaneous# Abstinence# Coitus interruptus# Safe period/Rhythm method/Calendar method/Ogino method# Natural family planning- Basal body temperature- Cervical mucus (Billing's method/ovulation method)- Symptothermic (combination of temperature, cervical mucus, and calendar technique)# TERMINAL: -Male sterilization and -Female sterilizationDrawbacks of the Calendar Method of Contraception# If cycle is irregular, it is difficult to predict the safe period.# It is possible only for use by educated and responsible couples with high motivation and cooperation.# Compulsory abstinence of sexual intercourse for nearly 1/2 of every month is required (programmed sex).# It has high failure rate up to 10 per 100 woman years.# It is applicable during the postnatal period.# Ectopic pregnancies and embryonic abnormalities have been reported as result of safe period method use.", 'role': 'assistant'}]