单选39.对于气动执行器的性能描述不正确的是(   )。

A、<span style="font-size:16px;font-family:宋体">系统结构简单&nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</span>

B、<span style="font-size:16px;font-family:宋体">推动力最大</span>

C、<span style="font-size:16px;font-family:宋体">安全性好&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</span>

D、<span style="font-size:16px;font-family:宋体">价格便宜&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span>