Bounding of section-lined regions: In a section view, the hatched (section-lined) area should be completely bounded by a visible outline of the cut region.

Introduction / Context:
Section views reveal internal geometry by depicting the areas physically intersected by the cutting plane. Hatching is limited strictly to those areas and must be bounded cleanly to avoid misrepresenting shape or material continuity.

Given Data / Assumptions:

• The visible outline of the cut surface appears as bold object lines in the section view.
• Hatching (e.g., ANSI 31 or other patterns) fills the interior of that outline.
• Hidden lines do not bound hatch; boundaries are visible cut edges only.

Concept / Approach:
Clarity in sectioning demands that hatch never spills beyond the cut surface and never relies on hidden geometry to define its edge. The boundary is the “profile” of the cut. Maintaining a closed, visible outline ensures readers understand precisely what material is being cut.

Step-by-Step Solution:
Establish the cutting plane in the parent view.Generate the sectional outline (the silhouette of the cut faces) with visible object lines.Apply hatch within that closed outline; do not cross object boundaries or open gaps.Confirm that all hatched regions are fully enclosed by visible lines.

Verification / Alternative check:
Compare standard examples: all hatched zones stay strictly within closed object-line boundaries. Breaks or leakage across boundaries are drafting errors.

Why Other Options Are Wrong:
“Incorrect” conflicts with sectioning rules. Limiting correctness to cast parts or assemblies misunderstands that the rule applies universally. Hidden lines are not used to bound hatch; they are omitted in sectioned regions unless necessary for clarity.

Common Pitfalls:
Leaving tiny unbounded gaps in complex shapes; applying hatch across fillets without respecting edges; using hidden lines to constrain hatch.

Final Answer:
Correct