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': 'Natural family planning method - \nSelect and explain. \nA. Abstinence, B. Coitus interruptus, C. BBT, D. Safe period', 'role': 'user'}, {'content': "Answer: C \nExplanation: Natural Family planning Methods Basal body temperature Depends on : Rise of temperature (0.3deg - 0.5degC) at ovulation. Occurs due to : Increased progesterone production Cervical Mucus method Also known as 'Billing' s Method' or 'Ovulation method' Based on changes in characteristics of cervical mucosa 1.At ovulation : Watery, clear, smooth, slippery, profuse (like egg White) 2. After ovulation : Thickens and lessens in quantity Symptothermic method Combines temperature, cervical mucus and calender techniques Ref: Park 25th edition Pgno : 559", 'role': 'assistant'}]