在圆柱坐标系中的矢量场，<img src="https://static.zxtiku.com/wangke/imgs/topic/879b518b11d420c74e228a7f2f098c25.jpg"/>，<img src="https://static.zxtiku.com/wangke/imgs/topic/67afb3d0f801e53d4d25fed35f1628ed.jpg"/>在点(2,0,3)处的值为（）<br/> A、0<br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/f7c5605e33f2ffd681f8ebba10e30e63.jpg"/><br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/ada53bd4feeaa2617a576f56c66bd3f3.jpg"/><br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/72804e5d3272669038d9d01869da9f04.jpg"/>