Question

what was one cause of the spanish - american war?
the belief that a spanish mine had blown up the battleship maine
theodore roosevelts interest in increasing the size of the navy
president mckinleys enthusiasm for going to war
cuban intervention in u.s. affairs

Explanation:

The sinking of the USS Maine in Havana Harbor, with widespread public and political belief that a Spanish mine was responsible, was a major immediate cause of the Spanish-American War. The other options are incorrect: Roosevelt's naval expansion was a broader policy, not a direct war cause; McKinley was initially hesitant to go to war; Cuba did not intervene in U.S. affairs, rather the U.S. intervened in Cuban affairs under Spanish rule.

Answer:

the belief that a Spanish mine had blown up the battleship Maine