请教大全-868代词指代的用法，谢谢！：）

大全-868  

To ensure consistently high quality in its merchandise, the chain of retail stores became involved in every aspect of their suppliers’ operations, dictating not only the number of stitches and the width of the hem in every garment as well as the profit margins of those suppliers.

(A) their suppliers’ operations, dictating not only the number of stitches and the width of the hem in every garment as well as

(B) its suppliers’ operations, dictating not only the number of stitches and the width of the hem in every garment as well as

(C) their suppliers’ operations, dictating not only the number of stitches and the width of the hem in every garment but also

(D) its suppliers’ operations, dictating not only the number of stitches and the width of the hem in every garment but also（D）

(E) their suppliers’ operations, dictating the number of stitches, the width of the hem in every garment, and

请问这里用their指代stores可以吗？这里the  chain  of是指零售商之间的连锁关系吗？难道说the chain 的 suppliers' operations？偶不理解这里代词指代的问题，麻烦哪位XDJM给解答一下，谢谢~~~！

所以D才对啊，用its=the chain of stores，用their来指代retail stores用语法上是可以的，关键是the chain of retail stores知道它的中心词是什么，相信你能解决