请教一道语法题

        In the face of widespread concern about environmental waste, compact disc manufacturers are attempting to find a replacement for the disposable plastic box in which they package their product.

(A) the disposable plastic box in which they

(B) the disposable plastic box where they

(C) a disposable plastic box in which to

(D) disposable plastic boxes inside which they

(E) the disposable plastic boxes in which to

答案是A,A和B有什么区别吗?

恩，对于GMAT来说，in which是更准确的。