A、<img width="23" height="20" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/4e4ae422-4132-48ec-97fd-18a70576fb46.png" />
B、<img width="33" height="21" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/65e49814-c162-4bb9-9229-a7d151da3a86.png" />
C、<img width="31" height="21" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/375a71f5-f3e6-4768-abda-216615f8e7c8.png" />
D、<img width="39" height="24" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/9c134b2e-8009-4deb-b222-89c31c9ad19a.png" />
查看答案
，则下列离子中最强的还原剂是（ ）。