## Core Concept
The question pertains to methods of waste disposal, particularly focusing on their impact on soil building. It requires knowledge of environmental health and waste management strategies.

## Why the Correct Answer is Right
Composting is a process that involves the breakdown of organic materials, such as food waste and yard trimmings, into a rich soil amendment. This method not only helps in managing waste but also enhances soil fertility and structure, making it beneficial for soil building. Composting is an eco-friendly way to recycle organic waste, reducing the need for chemical fertilizers and decreasing landfill waste.

## Why Each Wrong Option is Incorrect
- **Option A:** Incineration is a waste disposal method that involves burning waste materials. While it reduces the volume of waste, it does not contribute to soil building and can release harmful pollutants into the atmosphere.
- **Option B:** Landfilling involves burying waste in the ground. Although it is a common method of waste disposal, it is not beneficial for soil building. In fact, landfills can produce methane, a potent greenhouse gas, and leachate, which can contaminate groundwater.
- **Option D:** Recycling involves converting waste materials into new products to prevent waste of potentially useful materials. While recycling is beneficial for conserving natural resources and reducing landfill waste, it does not directly contribute to soil building like composting does.

## Clinical Pearl / High-Yield Fact
A key point to remember is that composting not only helps in waste management but also produces a valuable resource that can improve soil health, increase crop yields, and support sustainable agriculture. This method is particularly relevant in the context of environmental conservation and public health.

## Correct Answer: C.