The united states declaration of war on spain in 1898 is an example of

The correct answer to this open question is the following.

The United States declaration of war on Spain in 1898 is an example of "retaliation."

This is so because the Spanish Army had sunk the USS Main that was anchored close to the shores of la Havana, the capital city of the Island of Cuba. The Ship was there to closely follow the incidents of the Cuban independence movement against Spain when an explosion sank the navy ship. The United States declared war against Spain in what was known as the Spanish American War from April 1898 to August 1898. The US won the war.  

austria

hugary

yugoslavia

czechoslovakia

silk

indigo  

rice

all the other answers are wrong