Census data are most useful for which study in human geography?
The governing concept is the use of population statistics in human geography. A census is a systematic enumeration of people and households, usually including variables such as age, sex, literacy, occupation, residence, and sometimes migration or housing conditions. These data help geographers describe population structure, calculate densities, compare regions, and study how people are distributed across space. Therefore option A is correct. The age of rocks belongs to geology, ocean salinity belongs to physical oceanography, and daily pressure changes belong to meteorology. Although census operations may include geographic location, they do not primarily measure rocks, seawater, or atmospheric pressure.