Final answer:
The fall of the Soviet Union solidified the United States as the world's only superpower, marking the end of the Cold War bipolarity and establishing the US as the preeminent global power in terms of political influence, military might, and economic superiority.
Step-by-step explanation:
The fall of the Soviet Union affected the United States in several significant ways. Of the options provided, the most accurate is that it solidified the United States as the world's only superpower. The collapse of the Soviet Union meant the end of the Cold War bipolarity and the emergence of the US as the unchallenged global hegemon both economically and militarily. This shift turned the United States into the primary influence in international relations and global policy.
During the post-Cold War era, the United States engaged in supporting democratic reforms and economic development in the newly independent states that arose from the dissolution of the Soviet Union. This effort often saw the US playing the role of a world's policeman, stepping in to provide both political stability and military assistance as needed. This period also saw a transition as these states, including Russia under the leadership of President Vladimir Putin, navigated their newfound sovereignty with varying degrees of conflict and peace.
The ultimate effect of the Soviet Union's fall was the hegemony of the United States, as America's dominant cultural, military, and economic status led to a unipolar world system focused around its influence, a status that brought with it both the opportunity for widespread global influence and the responsibility of managing the stability of the international order.