Concept:A socio-economic factor is linked to human society and economic activity, unlike physical features such as soil or climate.Explanation:Soil type and rainfall distribution are physical and climatic factors, not socio-economic ones.Working capital is an economic factor that affects farm operations, but it does not directly reduce the physical availability of land.Population growth increases the demand for land for housing, settlement, and farming, thereby reducing the land available for agricultural use.Answer:B. population growth