- the highest MAC address available on the router, the FE80::/10 prefix, and the EUI-48 process
- the FE80::/10 prefix and the EUI-48 process
- the MAC address of the serial interface, the FE80::/10 prefix, and the EUI-64 process
- an Ethernet interface MAC address available on the router, the FE80::/10 prefix, and the EUI-64 process
Explanation: Since serial interfaces do not have MAC addresses, OSPFv3 automatically assigns a link-local address to them derived from the first available MAC address from the pool of Ethernet interface addresses on the router. A FE80::/10 prefix is added. The router then applies the EUI-64 process to the MAC address by inserting FFFE into the middle of the existing 48-bit address and flipping the seventh bit.