The events shown on the map correspond to the so-called Tet Offensive, so the correct answer is A, as American popular support for the Vietnam War declined after the Tet Offensive.
The Tet offensive was a great surprise attack launched by the North Vietnamese army and the Viet Cong during the Vietnam war. The offensive was launched on the night of the Vietnamese New Year (Tet Nguyen Dan), between 30 and 31 January 1968 and took place during the presidency of Lyndon B. Johnson.
The attacks of the communist forces affected virtually all the major cities of South Vietnam and initially achieved remarkable successes by catching the American and South Vietnamese forces unprepared. After violent clashes and heavy losses on both sides, the American and South Vietnamese forces retaked control of the situation, regaining the positions initially lost.
The Tet offensive was a decisive moment in the Vietnam war; despite the lack of military success, it constituted a great moral and propaganda victory for the Viet Cong and Northern Vietnam and caused a serious political and psychological crisis in the United States. Within a few weeks President Lyndon Johnson decided to withdraw from political life and stop the escalation, beginning peace talks.
