Final answer:
The true statement about unions is that they were started to protect the American worker, serving as organizations that advocate for workers' rights and interests, especially since the 1930s after the establishment of key legislation. Therefore, the correct option is A.
Step-by-step explanation:
Among the provided options, the true statement about unions is: a. Unions were started to protect the American worker. Unions were, and still are, organizations that represent the interests and rights of workers. Particularly in the history of U.S. unions, the growth in union membership in the 1930s was significant, following the passage of the National Labor Relations Act of 1935, which granted workers the right to organize unions.
Furthermore, during World War II, the U.S. government encouraged union formation to assist in production efforts. Post-war enactment of the Taft-Hartley Act of 1947, however, led to a decline in union membership as it allowed workers to opt out of unions. Unions have also engaged in advocacy around technological changes and working conditions, providing workers with a collective voice in contrast to the power of management.