Explanation:

- Demography (Option:2) is the correct term for the study of human populations, including their size, composition, and distribution across space, and the processes through which populations change. It is a key field in understanding social and economic trends and planning.

- Ethnography (Option:1) is the study of cultures and customs of individual peoples and communities. It focuses on qualitative data to understand social interactions and cultural patterns.

- Topography (Option:3) involves mapping and describing physical features of an area. This is more related to geography than human populations.

- Stenography (Option:4) is a method of writing quickly, often used for transcription, and is unrelated to population studies.

So, the correct answer is:

- Option:2 - Demography

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