A、<img width="13" height="37" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-23/585e322a-3370-4806-aace-fcb741cca04a.png" />
B、<img width="13" height="36" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-23/0cbc0d41-366b-4c26-b651-23b264248b78.png" />
C、1.5
D、3