Is responsible to the secretary of defense for u. s. military relations with 53 countries, including the islands of cape verde, equatorial guinea and sao tome and principe, and the indian ocean islands of comoros, madagascar, mauritius, and seychelles?

The correct answer is USAFRICOM

This is short for United States Africa Command and it is one of the nine commands that are part of the United States armed forces. They are in charge of solving conflicts or having military operations in all of Africa except in Egypt which falls into the domain of the central command. The head of it reports to the secretary of defense.