问题如下图：
选项：
A. 
B. 
C. 
解释：
老师你好，这道题目考查的知识点是哪个呢？谢谢解答🙏
NO.PZ2017092702000106 问题如下 The best approafor creating a stratifieranm sample of a population involves: A.awing equnumber of simple ranm samples from easubpopulation. B.selecting every kth member of the population until the siresample size is reache C.awing simple ranm samples from easubpopulation in sizes proportionto the relative size of easubpopulation. C is correct. Stratifieranm sampling involves ving a population into subpopulations baseon one or more classification criteriThen, simple ranm samples are awn from easubpopulation in sizes proportionto the relative size of easubpopulation. These samples are then pooleto form a stratifieranm sample.分层随机抽样涉及根据一个或多个分类标准将总体划分为子总体。 然后，从每个子群中抽取简单的随机样本，其大小与每个子群的相对大小成正比。 然后合并这些样本以形成分层的随机样本。 这道题的b说的是systematic sample嘛
selecting every kth member of the population until the siresample size is reache awing simple ranm samples from easubpopulation in sizes proportionto the relative size of easubpopulation. C is correct. Stratifieranm sampling involves ving a population into subpopulations baseon one or more classification criteriThen, simple ranm samples are awn from easubpopulation in sizes proportionto the relative size of easubpopulation. These samples are then pooleto form a stratifieranm sample.不太明白A错在哪里？既然是subpopulation了，不就是代表了已经分层了吗？
c老师能大概翻译下吗
可不可以帮忙把abc翻译一下？
