Correct Answer: Alluvium

Solution : The fourth option is the correct choice.

Alluvium is the soil deposited by flowing water, typically found in riverbeds and floodplains. It is often rich in minerals and nutrients due to the deposition of sediment carried by the water.

The meanings of the other options are as follows:

• Humus is decomposed organic matter in soil, resulting from the decay of plant and animal material.
• Clay is made of fine particles of soil that are cohesive and sticky when wet, often forming a compact structure.
• Loam is a soil type with a balanced mixture of sand, silt, and clay, providing good fertility and drainage.