Which of the following refers to the art of arranging the external physical environment to support human behavior?

The correct answer is clearly site planning, as it encompasses the comprehensive process of organizing the physical environment to optimize its functionality for human activities. This involves considering various factors, including land use, accessibility, aesthetics, and the interaction between different spaces.

Site planning involves strategic decision-making about the placement of buildings, roads, utilities, green spaces, and other elements to create a harmonious relationship between structures and their surroundings. The goal is to create environments that facilitate specific behaviors and enhance the quality of life for users.

In contrast, site development usually refers more specifically to the process of transforming a site for a particular use, which may include construction and other physical alterations. Landscaping focuses on the design and arrangement of outdoor spaces, particularly in relation to plants and natural features, rather than the broader implications of how the environment impacts human interaction. Urban design does encompass broader elements of shaping cities and public spaces, but site planning is more focused on specific sites and their functionality in relation to human behavior.