A、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/d7c264c6-3f76-4c50-9d53-be581a10d3e9.png" width="13" height="37">
B、<img src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/8c454adb-b740-4bf3-b3e4-20f904cccfc9.png" width="13" height="36">
C、1.5
D、3