The correct option is "all of these"
Richard Milhous Nixon It ended with the US intervention in the Vietnam War in 1973. Nixon's visit to China in 1972 established diplomatic relations between the two nations. Along with Secretary of State Kissinger, he redefined the role of the United States on the world stage. A gradual withdrawal of the 500,000 US soldiers fighting in South Vietnam was carried out, although the withdrawal lasted for four years. His greatest achievement was his approach and opening of relations with the People's Republic of China.
