The correct answer is option B: Garbage is separated into useful and non-useful components and then spread over the landfill site.

**Explanation:**

Garbage disposal is an essential part of waste management to ensure the cleanliness and hygiene of our surroundings. Landfills are one of the most common methods used for garbage disposal. In a landfill site, garbage is properly managed to minimize its negative impact on the environment.

Below is a detailed explanation of how garbage is handled at a landfill site:

**1. Collection and Transportation:**
Garbage is collected from various sources such as households, commercial establishments, and industries. It is then transported to the landfill site using garbage trucks or other suitable means of transportation.

**2. Initial Sorting:**
Upon arrival at the landfill site, the garbage is sorted to remove any large or hazardous items that may pose a risk to the environment or workers. This initial sorting helps in ensuring the safety and efficiency of the landfill operations.

**3. Separation of Useful and Non-useful Components:**
After the initial sorting, the garbage is further separated into useful and non-useful components. This separation process involves sorting the waste into different categories such as organic waste, recyclable materials, and non-recyclable waste.

**4. Composting of Organic Waste:**
Organic waste, such as food scraps and garden waste, is separated and processed through composting. Composting is a natural decomposition process that converts organic waste into nutrient-rich compost, which can be used as a soil conditioner in agriculture and gardening.

**5. Recycling of Recyclable Materials:**
Recyclable materials like paper, plastic, glass, and metal are separated and sent to recycling facilities. These materials are processed and converted into new products, reducing the demand for raw materials and minimizing the amount of waste sent to landfills.

**6. Disposal of Non-recyclable Waste:**
Non-recyclable waste, which cannot be composted or recycled, is spread and compacted over the landfill site. This process helps to reduce the volume of waste and creates additional space for future waste disposal.

**7. Environmental Protection Measures:**
To minimize the environmental impact, landfill sites are designed with liners and collection systems to prevent the contamination of groundwater and soil. Additionally, methane gas generated by the decomposition of organic waste is captured and used as a source of renewable energy.

By separating garbage into useful and non-useful components, landfill sites can effectively manage waste disposal while promoting recycling and composting. This approach helps reduce the amount of waste that ends up in landfills and contributes to a more sustainable waste management system.