What is the maximum required setback of the face of a structure from the toe of a slope?

The correct answer is based on regulations regarding the maximum setback distance necessary to ensure safety and stability when constructing near slopes. The term "H" refers to the height of the slope.

For option B, the maximum required setback is defined as H/2 (which is half the height of the slope) plus an additional distance of 15 feet. This requirement is in place to mitigate risks associated with erosion, landslides, and structural instability that can result from water runoff and other soil dynamics. By having a setback of H/2 plus 15 feet, it provides a buffer that helps ensure the integrity of both the structure and the slope.

Such regulations are important for maintaining safety standards in construction and ensuring that buildings are not placed at risk by proximity to potentially unstable ground. This requirement is often enforced in planning and zoning regulations to protect both the property and the surrounding environment.

Other options suggest different additional distances from the slope, which may not provide the necessary safety margins established by building codes and engineering considerations. Therefore, the choice of H/2 and 15 feet reflects a careful balance of risk management in relation to slope stability and construction practices.