用样本均数推论总体均数95％可信区间的公式是（总体标准差未知且样本量较小）（）

A、<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">&rho;ｔ0.05，&upsilon;S<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">

B、<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">&rho;ｔ0.01，&upsilon;S<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">

C、<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">&rho;1.96S<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">

D、<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">&rho;2.58S<img src="https://img.ppkao.com/2015-11/yeni/2015111611293963545.jpg">

E、以上都不对