多电平逆变电路的目的是使输出波形接近 ________ 。

A、<span style="font-size:14px;font-family:宋体">三角波</span><span style="font-size:14px;font-family:&#39;Times New Roman&#39;,&#39;serif&#39;">&nbsp;</span>

B、<span style="font-size:14px;font-family:宋体">方波</span>

C、<span style="font-size:14px;font-family:宋体">梯形波</span>

D、<span style="font-size:14px;font-family:宋体">正弦波</span>