Final answer:
The remaining portion of a multicast MAC address is created by converting the IPv6 address. Specifically, it is derived from the last 23 bits of the IPv6 multicast address, appended to a fixed starting sequence of the MAC address.
Step-by-step explanation:
The question pertains to how multicast MAC addresses are generated in relation to associated IP addresses, specifically within the context of networking and Internet protocols. When a multicast IPv6 address is in use, a multicast MAC address needs to be created. This is done by converting the last 23 bits of the IPv6 multicast address into the remaining portion of the multicast MAC address. The multicast MAC address begins with a fixed value (01-00-5E for IPv4 or 33-33 for IPv6), and these bits are appended to it to ensure the uniqueness of the multicast MAC address within the local network segment.
The correct answer to the question, 'The remaining portion of the multicast MAC address is created by converting a) The IPv6 address', as the IPv6 protocol dictates the method for translating an IPv6 multicast address to a corresponding MAC address.