对于 S7-200 PLC ，并联电路的串联指令是 （  ）

A、<span style="FONT-FAMILY: &#39;Times New Roman&#39;,&#39;serif&#39;; COLOR: black; FONT-SIZE: 14px">ORI </span>

B、<span style="FONT-FAMILY: &#39;Times New Roman&#39;,&#39;serif&#39;; COLOR: black; FONT-SIZE: 14px">ORB</span>

C、<span style="FONT-FAMILY: &#39;Times New Roman&#39;,&#39;serif&#39;; COLOR: black; FONT-SIZE: 14px">ALD</span>

D、<span style="FONT-FAMILY: &#39;Times New Roman&#39;,&#39;serif&#39;; COLOR: black; FONT-SIZE: 14px">OR</span>