Which surface roughness category indicates urban southern areas with closely spaced obstructions?

The correct choice indicates surface roughness characteristic of urban southern areas where closely spaced obstructions are present. This category, referred to as Exposure B, involves the conditions typical in urban settings, such as buildings, trees, and other structures that create turbulence and can affect wind patterns. The designation helps in assessing wind loads for buildings and structures, reflecting how these obstructions influence wind speeds and patterns near the earth's surface.

Understanding Exposure B is crucial for contractors and engineers when designing structures in urban environments, as it ensures they account for the increased wind turbulence caused by such obstructions. This consideration is particularly important in Southern urban areas, where the density of structures can significantly alter wind effects compared to more open areas. The categorization allows professionals to apply the appropriate safety factors in design calculations in line with the Building Codes and standards for effective structural integrity and performance.