Final answer:
White matter primarily consists of axons, while gray matter is composed of neuronal cell bodies and interneurons.
Step-by-step explanation:
White matter primarily consists of axons, which are responsible for transmitting signals throughout the nervous system. On the other hand, gray matter is composed of neuronal cell bodies and also the interneurons, which connect different neurons together. Therefore, the correct option is 1) White matter: Axons, Gray matter: Neuronal cell bodies.