The correct answer to this open question is the following.
Although there are no options attached or further references or context, we can comment on the following.
Cuba, Haiti, and the Dominican Republic were vital to emerging American power in the Caribbean because these Caribbean islands represented a strategic region for the economic and political interests of the United States.
That is why the United States government decided to support the independence of Cuba from the Spanish Crown, which derived in the Spanish-American War of 1898. The American presence in the Caribbean has been important to maintain and increase trade and strengthen relationships.
That is why the US government was so interested in the overthrow of Cuban Communist Dictator Fidel Castro during the Cold War years. He had close relationships with the Soviet Union and this issue went to extremes with the Cuban Missile Crises of October 1962, when the world was on the brink of another Worl War.