The correct answer would be A. the Legislative Power of the 3 branches of the government.
Because the presidential power is held under the Executive Branch, the answers would not be b, c, or d since all of those powers are under the executive branch. The president is granted the power of the military under the first article of the US Constitution which states all the powers of the Executive.
There were lots of foreign changes that presented challenges for the US. I'll give you a few examples from different time periods. First would be when England wanted to tax the Americans in the Revolutionary period. They did this to try and restrict America's freedom. Another example would be that Russia had spies during the cold war period. This was to gain intelligence of the US war plans. Also when Germany sent the Zimmerman Telegram to Mexico during the WWII period. This was to get Mexico to launch a surprise attack on the US.
