I believe the answer is C, hope this helped
B. The United States built a series of defensive fortifications in the 1950's called the Iron Curtain.
The Iron Curtain referred to the satellite nations that Russia controlled that acted as buffer between Western Europe and Russia.
<span>The main driver of the downfall of the shogunate was the exposure to outside countries, specifically their weapons systems. The shogunate had made very limited use of firearms. However, outsiders, such as Admiral Perry, made clear just how far the Japanese were behind in terms of their military capabilities. This drove the overthrow of the shogunate and the beginning of the Meiji period of modernization.</span>
The continental army's victory at saratoga