This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Currently, the threshold of bility lies between \nSelect and explain. \nA. 20 and 26 weeks, B. 24 and 28 weeks, C. 26 and 30 weeks, D. 28 and 30 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Threshold of ViabilityBihs once considered to be "abouses" because the fetus weighed <500 g are now classified as live bihs. For those newborns delivered before 33 weeks\' gestation, perinatal and neonatal care has advanced tremendously. As a result, the threshold of bility, which is the lower limit of fetal maturation compatible with extrauterine survival, has been reassessed. Currently, the threshold of bility lies between 20 and 26 weeks\' gestationReference: William\'s Obstetrics; 25th edition; Chapter 42; Preterm bih', 'role': 'assistant'}]