Which of the following surfaces is typically excluded from friction surface regulations?

The correct choice directly pertains to the specific regulations that apply to friction surfaces, particularly in the context of building codes and safety standards concerning slip resistance. Masonry treads are often excluded from these regulations because they are typically not designated as "friction surfaces" in the same way that other surfaces, like stair treads or door edges, are.

Friction surface regulations are focused primarily on areas that people frequently walk on, such as stair treads, which require specific characteristics to ensure safety against slips and falls. Wooden door edges and door jambs also face different safety considerations that do not align with typical slip resistance requirements. Therefore, masonry treads, often used in situations where intended foot traffic is less frequent or where additional factors (such as texture and material) are considered, do not fall under the same friction surface mandates.