Answer:
"Western European capitalist country" would have been most likely to join the North Atlantic Treaty  Organization.
Explanation:
The North Atlantic Alliance or North Atlantic Treaty Organization is an intergovernmental defensive alliance involving 29 nations of North America and Europe. The council is enforcing the Treaty of the North Atlantic established on April 4, 1949.
The main function of NATO was to safeguard the member countries from interventions by communist nations. The United States wanted to maintain a foothold in Europe, too. This sought to avoid violent nationalism from resurging and to promote political union.
