The introduction of gunpowder gradually made the bow and arrow ________, particularly in Western Europe.
句意：火药的引入逐渐使弓和箭过时了，特别是在西欧。obsolete过时的；废弃的；老式的。 obscure昏暗的，朦胧的。optional可选择的，随意的。overlapping重叠；覆盖。故选B。