The correct answer is He thought they were necessary to oust a Communist-leaning government in Nicaragua.
One of Reagan's most important policies was fighting communism on a global scale. One place where communist was prevelant was Nicaragua. A group called the Sandinistas overthrow the government of Nicaragua in order to establish a communist regime. The group that opposed this communist overthrow was the Contras. This is why answer three is correct.
Written jointly by Marx and Engels from December 1847 to January 1848, The Communist Manifesto was first published on 21 February 1848. The Communist Manifesto laid out the beliefs of the new Communist League.