Why is Kennedy's repeated claim "Ich bin ein Berliner" ("I am a Berliner") especially effective for his West Berlin audience in 1963?

A. It tells Berliners that Kennedy will lead the fight against communism.

B. It reminds Berliners that the world is watching how they adapt to communism.

C. It demonstrates that Kennedy identifies with his audience and supports Berliners in their struggles.

D. It emphasizes Kennedy's belief that communism is only an issue in Berlin.