Final answer:
A pinhole models the geometric shape of a cone, as light creates a conical form when it passes through a small aperture.
Step-by-step explanation:
The geometric shape modeled by a pinhole in the wall is represented by a cone. When light passes through a small pinhole, it spreads out in all directions from the point of the pinhole, forming the shape of a cone.
This is consistent with the concept of conic sections which are formed by the intersection of a plane with a cone, and can be identified as circle, ellipse, parabola, and hyperbola. The correct answer to the question is d) Cone.