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

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.

the north atlantic treaty organization (NATO)