The correct answer is that it led to the U.S. declaring war on Spain, from whom Cuba was fighting for independence, in 1898. However, we need to make a few reservations about this.
Today is no longer believed that the explosion of the U.S.S Maine was so important to the deflagration of the Spanish- American-Cuban-Filipino war. We know now that by the results the U.S. pursued during and after the war, this war was an imperialist move: Americans needed more consumer market and source materials for their growing industry.
After the war, the U.S. occupied Philipines, annexed Hawaii, and turned Cuba into some sort of protectorate. This opened up China's and Latin America's markets for American goods.