The correct answer is option D "The Cavalry unit of the Rough Riders victory". The Spanish-American war was one sided from its beginning as US army was many times more powerful than the Spanish army. During the war Gen. William Shafter led an army of volunteers and regular troops called "the Rough Riders" (army than included Theodore Roosevelt). This army forced Spanish forces to retreat from Cuba, and in the coast US forces destroyed what was left of the Spanish army.