GB／T19472.1－2004中公称内径为500mm，环刚度等级为SN8的PE双壁波纹管材的标记为（)A、双壁波纹

GB/T19472.1-2004中公称内径为500mm，环刚度等级为SN8的PE双壁波纹管材的标记为()

A、双壁波纹管PE/ID500SN8GB/T19472.1-2004;

B、双壁波纹管PEDN/ID500SN8GB/T19472.1-2004;

C、双壁波纹管PEPDN/ID500SN8GB/T19472.1-2004;

D、双壁波纹管PPDN/ID500SN8;