Final answer:
Option (A), The Spanish-American War marked the emergence of the United States as a global military power, leading to its expanded role in international affairs, making answer A correct.
Step-by-step explanation:
The Spanish-American War was a turning point in U.S. History because it represented a moment when the United States emerged as a significant military power with expanded global influence. The correct answer to the question is A. After the war, the U.S. took a larger role in world affairs. This was due in part to the acquisition of former Spanish territories such as Puerto Rico, Guam, and the Philippines, marking the United States' advent into imperial status and its participation in international politics at a higher level.
The explosion of the USS Maine, while a catalyst for declaring war, was not a turning point in itself but rather part of the events leading up to the war that garnered public support for intervention. Additionally, Theodore Roosevelt's heroic image was bolstered by his participation in the war, elevating his political career that eventually led to the presidency, rather than marking its end.