Among the following, which tree is classified as a hard angiosperm?

Mahogany exemplifies a hard angiosperm because it belongs to a group of flowering plants characterized by broad leaves and the production of seeds enclosed in fruit. Angiosperms, or flowering plants, are distinct from gymnosperms (like pine, cedar, and spruce) which have seeds that are not enclosed in an ovary.

As a hardwood, mahogany is particularly valued for its density and resilience, making it suitable for quality furniture and cabinetry. The properties of hardwoods typically include stronger and heavier characteristics compared to softwoods, which are derived from trees like pine, cedar, and spruce. These softwoods generally have needles and cones, and their foliage and reproductive structures differ significantly from hard angiosperms. This differentiation in plant structure is fundamental in categorizing them into angiosperms or gymnosperms. Thus, mahogany stands out as the correct choice among the listed options.