试题选项中表示延时断开动合触点图形符号的是(____)。
A<img src="/tupian/shandong/dinghongjian/dinghongjian13.jpg"/>
B<img src="/tupian/shandong/dinghongjian/dinghongjian14.jpg"/>
C<img src="/tupian/shandong/dinghongjian/dinghongjian15.jpg"/>
D<img src="/tupian/shandong/dinghongjian/dinghongjian16.jpg"/>