D is your answer, hope I was able to help!
This is because it was when the Allies were able to defeat the Axis powers, which gave hope to the Allies to fight stronger. Also, when they defeated Axis powers at that battle, they(ALLIES), now had vantage points on both sides of Germany; east(UK) and west (Russia).
I believe the answer is Austria.
C) to maintain a balance of power in Europe
The Sherman Antitrust act was created for that purpose, but it was also supported by the Clayton Antitrust Act which came later on. Roosevelt was known as "Teddy the Trust-Buster" for his strict enforcement of these acts.
