已知总体服从正态分布，且总体标准差σ，从总体中抽取样本容量为n的产品，测得其样本均值为，在置信水平为1-α=95%下，总体均值的置信区间为（　　）。

A、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/0a7c61ae-1642-4d36-b093-d5335613235d.jpg" width="165" height="41" />

B、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/36a17a73-12b8-44bf-9f73-ff14680e41aa.jpg" width="134" height="41" />

C、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/e376e308-c67a-4de4-8170-5ad4886aa630.jpg" width="135" height="37" />

D、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/e244fadc-4c7d-48fa-87cc-b8b523b90fe4.jpg" width="137" height="41" />