如图9.2所示曲柄连杆机构中OA 杆垂直于水平线OB，滑块B的速度为v，则AB杆的角速度为（）。

B、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/ee7b75ec-0c98-4ef4-8f5c-4ec313244e6b.jpg"title="1374808906519.jpg" alt="1374808906519.jpg"/>&nbsp;

C、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/442ea2f0-5791-40a0-b568-dfdfa8063a2b.jpg"title="1374808965973.jpg" alt="1374808965973.jpg"/>

D、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/4ed5acba-2eb4-4f98-a72c-315fc6af41f2.jpg"title="1374808975769.jpg" alt="1374808975769.jpg"/>