Although World War II ended nearly a half century ago, ... ...

   Although World War II ended nearly a half century ago, Russia and Japan still have not signed a formal peace treaty; and both countries have been reticent to develop closer relations.
(A)    have not signed a formal peace treaty; and both countries have been
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Writing Drills: Warm-Up Drill V