The correct option is D cranium
The brain and spinal cord are parts of the central nervous system. The brain and spinal cord are protected by bony structures called the cranium and vertebrae respectively. They are both covered by cranial meninges - dura, arachnoid and pia mater.
The brain is divided into forebrain, midbrain and hindbrain. The outer layer of the forebrain is called the cerebral cortex.