Final answer:
The correct answer is a. The battle that made Admiral George Dewey a hero was the Battle of Manila Bay, where the U.S. fleet destroyed the Spanish armada with no American combat casualties, signaling the end of Spain's colonial era and the rise of American imperialism.
Step-by-step explanation:
Dewey's Pacific fleet was positioned in Hong Kong prior to the outbreak of the Spanish-American War, ready to act upon the imminent conflict with Spain. As war erupted, Dewey was ordered to liberate the Philippines, another Spanish colony seeking independence. The battle on May 1, 1898, was the first significant military confrontation during the war, which saw a decisive American victory, as Dewey's fleet destroyed the Spanish armada stationed at Manila Bay. Not a single American life was lost during the confrontation, although one sailor died due to health issues, and only nine were injured, while the Spanish fleet suffered 371 casualties. Dewey's success at Manila Bay, capturing the Philippines, marked the end of Spain as a colonial power and began the emergence of the United States as a new empire with naval bases across the Pacific.
Commodore Dewey's command and leadership during the battle exemplify the U.S. strategy in implementing Alfred T. Mahan's vision for a robust and strategically placed naval fleet and embarking on America's imperialistic endeavors in the Pacific region, which went beyond the liberation of Cuba.