Which bone is located at the back of the head?

The occipital bone is the correct answer because it is situated at the back of the skull. This bone plays a crucial role in forming the base of the cranium and contains the foramen magnum, which is the opening for the spinal cord to connect with the brain. Its anatomical position makes it vital for protecting the brain and supporting the structure of the head.

The other bones listed have different locations and functions. The maxilla is found in the upper jaw and holds the upper teeth, the parietal bone is located on the sides and top of the skull, and the nasal bone forms part of the nose structure. Each of these bones serves distinct roles in facial structure or skull protection, but none are situated at the back of the head like the occipital bone.