Which of the following missions was NOT part of the Vietnam Police Action?

The mission that was not part of the Vietnam Police Action is the one involving surface ships conducting amphibious operations. The Vietnam Police Action primarily focused on a combination of unconventional warfare and counterinsurgency efforts, with an emphasis on land operations and limited naval support.

During this conflict, the U.S. military engaged in aerial reconnaissance to gather intelligence, conducted naval gunfire support to assist ground forces, and carried out coastal patrols to monitor enemy activities and protect shipping lanes. However, large-scale amphibious operations involving surface ships were not a significant component of the strategy employed in Vietnam, marking this option as the correct choice for the question. The emphasis in Vietnam was more on supporting ground troops and engaging in coastal activities rather than executing substantial maritime amphibious assaults.