The correct answer here is the third option.
The "domino effect" is a term used a lot over the course of the Civil War and it was explained by this quote by president Dwight D. Eisenhower and it refers to the communist situation in Indochina. He talked if the states fall there, communism will spread further. This lead to the US support of non-communist government of South Vietnam.
A benefit for a knight was they where very high on the nobility scale. Knights started at a young age. 7, I believe.
He was 56 years old when he was shot.
Answer:
A The military leaders freed the slaves that worked in the mine