What was one cause of the Spanish-American War?

Answer:
I think its A because I found this short-paragraph online
Explanation:
On April 21, 1898, the United States declared war against Spain. ... The reasons for war were many, but there were two immediate ones: America's support the ongoing struggle by Cubans and Filipinos against Spanish rule, and the mysterious explosion of the battleship U.S.S. Maine in Havana Harbor.