Concept:Loam is best for crop production because of its balanced texture and moisture properties.
Explanation:Loam contains sand, silt, and clay in balanced proportions.
It is porous, which allows air and water to move freely through the soil.
It also has good water retention capacity, so plant roots have steady moisture access.
Option B is incorrect because humus content depends on organic matter, not on the soil type alone.
Therefore, the correct reason is the combination of porosity and water retention.
Answer:C. porous and has good water retention capacity.