In which example can out-migration become a cause of population decline?

Correct answer: Many young people are leaving the area for work

The direct answer is C. Out-migration means people leave their usual area to live or work elsewhere. When many young people leave a region for employment, the local population is reduced directly, especially if the number leaving is greater than the number entering. It may also affect the age structure because the working-age group becomes smaller. Option C is correct because it describes people moving out of the area. Option A describes in-migration, which adds people to the receiving area rather than causing its decline. Option B describes positive natural increase because births exceed deaths; it does not describe out-migration. Option D describes an improvement in services, which may attract or retain people but is not itself out-migration. The final population still depends on births, deaths, arrivals, and departures together. Memory cue: “out” means people go out, so the local count can go down.