匀质圆盘的质量为 ，半径为r，若圆盘在光滑水平面上以速度 平动时，则圆盘动能T=（  ）。

A、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/82166971-f627-4f1e-bd48-a17f14247095.jpg"title="1374997584348.jpg" alt="1374997584348.jpg"/>&nbsp;

B、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/1ee400b2-d633-465a-957f-69505f7b15b5.jpg"title="1374997598332.jpg" alt="1374997598332.jpg"/>

C、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/8f8bdc56-bb75-4dce-8f7a-bff28236fb73.jpg"title="1374997607801.jpg" alt="1374997607801.jpg"/>