如图所示机构在图示位置时，AB杆转动的角速度为<img src="https://static.zxtiku.com/wangke/imgs/topic/874fd7b470b7cd6a7d2b66079ce37a82.jpg"/>、角加速度为零，AB、GC铅直，B、E两铰链位于同一水平线上，AB=BE=EC=ED=r。此时，滑块D在GC杆槽中滑动的相对加速度<img src="https://static.zxtiku.com/wangke/imgs/topic/b0f46eb2dfed4f2ea6a22de744fb668d.jpg"/>为()<img src="https://static.zxtiku.com/wangke/imgs/topic/58583779b654aff82c95ed6c9d23552b.jpg"/><br/> A、<img src="https://static.zxtiku.com/wangke/imgs/topic/7b7e08b65c725f4573266f46303fcde1.jpg"/><br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/0d8bfde0033fa95d5e90c4289bc47bae.jpg"/><br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/854d65b36c97269559ab25cb902b4f68.jpg"/><br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/f0e7f8aa89efd640efcfc9bfd4a08461.jpg"/>