The correct answer is C) Communism was spreading outside of Europe.
The main concern that led to the formation of SEATO and OAS was that Communism was spreading outside of Europe.
SETO stands for The South East Treaty Organization. The OAS stands for The Organization of American States. It was formed on September 8, 1954, and was created to block the spread of Communism in South Asia. It was signed by Australia, the United States, New Zeland, Pakistan, Thailand, the Philippines, Bangladesh, France, Hong Kong, and the United Kingdom.
The OAS was formed in 1948, in Bogota, Colombia, and has similar purposes, to stop Communism in America and to promote trade, military aid, and support for the American countries. Most of the American nations are part of OAS.
