Final answer:
b. convex
A profile with a prominent forehead and chin with other features set inward is a convex profile. Convex describes the outward curve of the profile's line of projection. This differs from straight, concave, or balanced profiles.
Step-by-step explanation:
A profile with a prominent forehead and chin, with other features receded inward, is referred to as a convex profile. This term is used to describe the curvature of the profile line when it is viewed from the side. In contrast to a convex profile, a straight profile would have roughly flat lines, a concave profile would present with a forehead and chin that are set back relative to the nose, and a balanced profile is one where all the facial features are in harmonious alignment without prominent protrusion or recession.