单选33.热电偶的输出信号为(    )

A、<span style="font-size:16px;font-family:宋体">电压&nbsp; &nbsp; &nbsp;</span>

B、<span style="font-size:16px;font-family:宋体">电流&nbsp; &nbsp; &nbsp;</span>

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

D、<span style="font-size:16px;font-family:宋体">温度</span>