Geographical distribution of population refers to how people are spread across different areas of a country or region. Several factors influence where people choose to settle, and among the options given, climatic conditions is the one that directly affects geographical distribution.
Areas with favourable climates (moderate temperatures, adequate rainfall, fertile soil) tend to attract denser settlements because they support agriculture, comfortable living, and economic activity. In contrast, regions with extreme climates (deserts, very cold areas, dense tropical forests) tend to be sparsely populated because they are less hospitable for farming and habitation.
Encouragement of early marriages in rural areas affects the rate of population growth (birth rate), not the spatial distribution of people across regions. High birth rate and high death rate are components of population change (natural increase or decrease), but they do not explain why people are concentrated in some areas and sparse in others. These factors influence the size of a population, not its geographical spread.
Climate, along with other geographical factors like terrain, water availability, and natural resources, is a primary determinant of where people live within a country.