The correct answer is:
Martin Luther King Jr.
The Montgomery bus boycott was a massive demonstration that had been sparked by the arrest of Rosa Parks on December 1955. It concluded with the U.S. Supreme Curt ruling as unconstitutional the segregation on public buses. It was organized by the Montgomery Improvement Association (MIA) and its president, Martin Luther King, Jr., who became a prominent civil rights leader as international attention focused on Montgomery.
Martin Luther King, Jr. would become a spokesperson for nonviolent protest by African Americans thanks to his use of the power of words and acts of nonviolent resistance.