127.0.0.1 is the IPv4 loopback address. Answer 00-21-86-5C-B4-6C is a mac address, while the remaining answers are IPv6 addresses, in IPv6 the loopback is ::1
In computer networking, localhost is a hostname that refers to the current computer used to access it. The name localhost is reserved for loopback purposes.
It is used to access the network services that are running on the host via the loopback network interface. Using the loopback interface bypasses any local network interface hardware.