The correct answer is C. Repetition of a phrase for emphasis
Step-by-step explanation:
Kennedy's speech on June 26 of 1963 referred to the situation of Berlin during that time as this was divided into west and east. Moreover, the west side was supported by capitalist countries, while the east country was supported by the communist countries, especially the Soviet Union.
In terms of rhetoric, in this speech, Kennedy uses multiple times the phrase "Let them come to Berlin" to convey the idea communism is negative and has had negative effects on Berlin. For example, in "There are some who say that communism is the wave of future. Let them come to Berlin" the phrases emphasize communism is not a positive form of government, and has had negative effects in the city, which also suggests this situation should end. Thus, the correct answer is C.