A、<img width="125" height="10" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/70c84d2c-3f67-4bb3-9e3e-5cb6536725b1.png" />
B、<img width="125" height="10" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/3ea7423e-3d63-429f-a88c-8077d03dd3f9.png" />
C、<img src="http://admintk.100xuexi.com/UpLoadImage/2016-08-05/4acec240-d5a7-43ed-9eb8-7f94dc48deb6.png" title="1.png" />
D、<img width="115" height="10" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/1ebd1e86-043c-4bf6-80b3-0039ef3a3286.png" />
查看答案
的波形为（ ）。
