The political cicumstances around the latin revolutions against the European colonies reminded most American leaders of the American Revolution. As a result they supported these struggles.
I'm thinking A because Saratoga is in the south. Hope this helps.
A key advantage was that the Soviet Union had been damaged by the Nazis invasion of their country and by the deaths of over 20 million people fighting them so it was weakened by the war unlike the US which had only suffered at Pearl Harbour but not in the mainland USA.
