Which of the following is a key part of the reform movement of the progressive era and has had a lasting influence on US thinking into the 21st century?

A. The woman's Christian temperance movement

B. American magazine

C. The Sierra club

D. Colliers magazine

A is false. The WCTU was founded in 1874 and since then it became one of the largest and most influential women's group ever. It was a religious organization and its primary purpose was to combat the influence of alcohol in society. It remains active nowadays. They operated at an international level and supported other very important causes during the 19th century including labor, public health, sanitation and international peace causes.

B is false. The American magazine has been active until 1956. It was

focused on human interest stories, social issues and fiction.

C is true. Sierra Club is an environmental organization founded in 1892 and with over three million members in activity since then. As a tradition, it's asociated to the progressive movement and it engages in lobbying politicians promoting environmental policies and supporting political activism to promote several causes. It's a large-scale environmental preservation organization.

D is false. Collier's was founded in 1888 and is considered a pioneer on investigative journalism and literature. It was published in the 19th and 20th centuries with an important presence in the lives of americans. But it ceased publication by 1957.