Concept:Soil texture is an innate property based on the proportions of sand, silt, and clay particles.
Explanation:A farmer can easily alter soil porosity through tillage or compaction practices.
Soil structure can be improved by adding organic matter or using proper cultivation methods.
Soil acidity can be corrected by applying lime or other amendments.
However, soil texture depends on the size distribution of mineral particles present in the soil.
Changing this particle size composition is practically impossible for a farmer.
Therefore, texture remains the most permanent and least manageable soil property.
Answer:C. Texture