Answer:
C) People who live in Berlin, Frankfurt, or Munich
Explanation:
Surveys are sent to the people in who live in the city limits of Berlin, Frankfurt, and Munich.
Therefore population in cities of Germany other than Berlin, Frankfurt, and Munich cannot declare their thoughts about government.
This means, people living cities other than Berlin, Frankfurt, and Munich are not represented in the survey, population represented in the survey are people who live in Berlin, Frankfurt, or Munich.