Caesar Chavez is best known for ...

• A. His leadership in the conservation movement.
• B. His efforts to gain better working conditions for farm workers.
• C. Founding a major banking coalition.
• D. Advancing space exploration programs.

Answer: (B)

The main idea being tested is identifying Caesar Chavez’s clear historical contribution: organizing and advocating for farm workers’ rights and better working conditions.

Chavez co-founded the United Farm Workers union and used nonviolent methods—strikes, boycotts, marches, and fasting—to push for fair wages, safer working conditions, and the right to collective bargaining for farm laborers. His leadership brought national attention to the plight of agricultural workers and helped bring about reforms that improved labor standards in farming communities.

That other areas don’t fit because they point to different figures and movements (environmental conservation, banking coalitions, or space programs), whereas Chavez’s lasting impact centers on protecting and improving the lives of farm workers.