某生化指标在人群中呈正态分布，制定其参考值范围常用（　　）。

A、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/fa0b6447-0199-44a1-9de9-51d2652a5233.png" width="19" height="21" />±SD

B、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/fa0b6447-0199-44a1-9de9-51d2652a5233.png" width="19" height="21" />±2SD

C、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/fa0b6447-0199-44a1-9de9-51d2652a5233.png" width="19" height="21" />±3SD

D、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/fa0b6447-0199-44a1-9de9-51d2652a5233.png" width="19" height="21" />±4SD

E、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/fa0b6447-0199-44a1-9de9-51d2652a5233.png" width="19" height="21" />±5SD