In a building section drawing, it is essential to showcase the details that help understand the internal structural framework and architectural details of the building. This includes:

• Plinth Height: This is the height of the portion of the building above the ground level and below the ground floor level of the structure. Knowing the plinth height is crucial for ensuring proper drainage and protection against moisture.
• Storey Heights: The vertical distance between finished floor levels, providing clarity on different levels within the building, which is necessary for planning and structural design.
• Thickness of Walls: It denotes how thick the walls are, affecting structural load, stability, and space utilization.
• Sizes of Structural Members: This includes beams, columns, slabs, etc., necessary for structural integrity and design calculations to ensure safety and compliance with standards.

The given correct set of details accords with these primary elements of a building section drawing. Let's rule out other options:

• Site boundaries, north direction, plot dimensions, and road access information: These are typically shown in a site or plot plan to understand the layout and orientation of the structure on the land, not in a section drawing.
• Location of furniture, electrical switch positions, drainage lines, and door numbers: These may be part of detailed interior layouts or electrical and drainage plans but not the section drawing.
• Carpet area, number of rooms, exterior color, and type of flooring used: These are part of material and interior specifications but not shown on a building section drawing.

Therefore, the option "Plinth height, storey heights, thickness of walls, and sizes of structural members" is indeed the correct set of details typically shown in a building section drawing. This ensures an understanding of the structural and architectural aspects necessary for constructing and assessing a building.