The statement that best describes the relationship that European communists and socialists had with their capitalist governments during World War II is:
European communists and socialists set up uneasy alliances with capitalists to defeat fascist and Nazi forces.
During the war, many communist and socialist groups collaborated with capitalist governments as part of a united front against the common threat posed by fascism and Nazism, despite their ideological differences. This alliance was often characterized by pragmatism rather than genuine agreement on economic or political principles.