What happens if the core shadow is placed too close to a correctly positioned highlight on a sphere?

Correct answer: The midtone will narrow and the form will appear to turn abruptly

The governing shading concept is the gradual value transition that communicates a sphere’s rounded form. A highlight should normally move through a sufficiently broad midtone before reaching the core shadow. If the core shadow is brought too near the highlight, that transition is compressed; the midtone becomes narrow and the surface appears to turn sharply instead of rotating smoothly. Transparency, cast-shadow length, and lighter local value do not follow from this placement, so B is correct.