The question asks about the additional information provided by a sectional elevation of a building drawing compared to a front elevation. Understanding various types of architectural drawings helps in identifying the right answer.

A sectional elevation is a type of architectural drawing that involves imagining a vertical cut through a building from top to bottom. This type of drawing allows us to see the internal configuration along the cut plane, offering insights that are not visible in a standard front elevation.

Let's evaluate each of the given options:

• Plot boundaries, setback distances, and site alignment details: These details are generally not specific to sectional elevations as they relate more to site planning and layout designs, which are more comprehensively addressed in site plans and key maps.
• Location of rooms, circulation passages, and furniture arrangement details: While a sectional elevation includes the layout of the spaces vertically, the detailed arrangement of furniture and specific circulation paths are typically shown in plan views/drawings.
• External appearance of walls, front architectural style, and side view details: These features are best depicted in front elevations or side elevations, rather than sectional elevations. They showcase the aesthetic elements of the building.
• Cut portions of structural elements, plinth levels, and foundation details: This is the correct answer. Sectional elevations provide in-depth insights into the structural elements that have been intersected by the vertical cut, such as columns, beams, plinths, and foundations, which are not visible in front elevations.

Therefore, sectional elevations are crucial for understanding the internal construction details such as where the structural components are cut, and give essential information about plinth levels and foundation details.