The Correct Answer:
The correct answer is option 'D' - "Voids of soil clogged due to continuous application of sewage on a piece of land."

Explanation:
Sewage sickness refers to the adverse health effects that can occur due to the improper handling and disposal of sewage. It is important to understand the various factors that contribute to sewage sickness in order to prevent and mitigate its impact.

1. Sewage Contains Pathogenic Organisms:
- Sewage is a mixture of domestic and industrial wastewater, which may contain pathogenic organisms such as bacteria, viruses, and parasites.
- These microorganisms can cause diseases such as diarrhea, cholera, typhoid fever, hepatitis, and gastroenteritis when they enter the human body.

2. Sewage Enters the Water Supply System:
- When sewage enters the water supply system, it can contaminate drinking water sources and lead to waterborne diseases.
- If sewage is not properly treated before being discharged into rivers, lakes, or groundwater, it can contaminate these water sources and pose a risk to human health.

3. Sewers Get Clogged Due to Accumulation of Solids:
- Sewers can become clogged due to the accumulation of solid materials such as grease, debris, and non-biodegradable items.
- Clogged sewers can lead to the overflow of sewage, causing it to back up into homes, streets, and other areas.
- This can result in the release of foul odors, the spread of disease-causing microorganisms, and the contamination of soil and water.

4. Voids of Soil Clogged Due to Continuous Application of Sewage on a Piece of Land:
- When sewage is continuously applied to a piece of land without proper treatment and management, it can lead to the clogging of soil voids.
- The accumulation of sewage solids and organic matter can block the natural flow of water through the soil, preventing proper drainage and percolation.
- This can result in the saturation of the soil, leading to waterlogging and the formation of anaerobic conditions.
- Anaerobic conditions promote the growth of harmful bacteria and the release of toxic gases, which can pose a risk to human health.

In conclusion, while all the options mentioned in the question can contribute to sewage sickness, the clogging of soil voids due to the continuous application of sewage on a piece of land can have significant health implications. It is essential to adopt proper sewage treatment and disposal methods to prevent sewage sickness and protect public health.