Final answer:
The bones best demonstrated on the 15-degree occipitofrontal projection are the frontal, parietal, and sphenoid bones.
Step-by-step explanation:
The cranial bones that are best demonstrated on the 15-degree occipitofrontal projection are the frontal, parietal, and sphenoid bones. Sphenoid bone is located at the base of the skull and forms part of the lateral wall of the skull. It is best demonstrated on the occipitofrontal projection due to its position. The frontal bone forms the forehead and part of the roof of the orbit, and the parietal bones form the sides and roof of the cranium.