The correct answer is b) nasal.
The orbit of the skull is a complex structure formed by several bones, which includes:
- Zygomatic bone: This bone forms the cheek and contributes to the outer edge of the orbit.
- Frontal bone: This is the bone that forms the forehead and the upper part of the eye socket.
- Ethmoid bone: This bone is located between the nose and the orbits, contributing to the medial wall of the orbit.
- Sphenoid bone: This bone is situated at the base of the skull and helps form the back of the orbit.
However, the nasal bone primarily forms the structure of the nose and does not contribute to the formation of the orbit. Thus, while it plays an important role in the facial skeleton, it is not part of the orbital bones.