The correct order to form a meaningful sentence is DBCAE. Part (D) introduces the action taking place, which is someone recounting a tale. Part (B) specifies the subject matter of the tale being recounted, namely the economic collaboration. Accordingly, DB forms a necessary pair. Part (C) provides further detail about the context of the tale, specifying the two nations involved in the economic collaboration. Part (A) specifies one of the outcomes or consequences of the economic collaboration and events recounted in the tale, namely societal transformations. Part (E) provides additional information about the tale being recounted, specifying that it is about events that ensued or followed a particular situation. Hence, (a) is the correct answer.
The complete sentence is: She is recounting a tale of the economic collaboration between the two nations and the societal transformations that ensued.