Which is an example of a regional security alliance?

the U. S. Agency for International Development (USAID)

the Marshall Plan

the North Atlantic Treaty Organization (NATO)

the United Nations

the north atlantic treaty organization (NATO)

An example of a regional security alliance is the North Atlantic Treaty Organization (NATO).

NATO is an intergovernmental military alliance governed by the North Atlantic Treaty, signed on April 4, 1949. The organization is a collective defense system, in which member states agree to defend any of its members if they are attacked by an external power.