Short Answer 
The excerpt discusses the postwar vision of President Roosevelt and Prime Minister Churchill, emphasizing their commitment to global peace and freedom after Nazi tyranny. They aim to ensure security, eliminate tyrannical threats, and guarantee individual rights, with a focus on a unified world, which is best captured in option (a) that highlights their broader mission.
Step 1: Understanding the Central Theme
The central theme of the excerpt revolves around the postwar vision articulated by President Roosevelt and Prime Minister Churchill. They express a collective aim to establish global peace and freedom following the end of Nazi tyranny. Their shared perspective is pivotal in shaping a world where nations can coexist without the threat of war or oppression.
Step 2: Emphasis on Security and Freedom
Roosevelt and Churchill stress the importance of creating a world where all nations can live securely and freely. This entails a commitment to ensure safety within national borders while promoting individual freedoms. Key elements of their vision include:
- Establishing lasting peace among nations.
- Eliminating the threats posed by tyrannical regimes.
- Guaranteeing the rights and liberty of individuals globally.
Step 3: Choosing the Accurate Summary
To encapsulate their goals, option (a) accurately reflects Roosevelt and Churchill’s intentions by stating that they are working to bring peace and freedom to people everywhere. This choice is more comprehensive than options that focus solely on defeating the Nazis or liberating specific regions, as it represents their broader mission for a unified world post-conflict.