Your network contains 10 subnets. Each subnet contains 10 servers that run Windows Server 2012 R2.
You plan to assign IPv6 addresses to all of the servers. The solution must ensure that the servers can connect
to other servers in remote subnets. The IPv6 addresses will not be routed on the Internet.
You need to identify a valid prefix to use for the IPv6 addresses.
Which prefix should you identify?

A.
Fd00::

B.
2002:

C.
Fec0::

D.
::1

Explanation:
https://4sysops.com/archives/ipv6-tutorial-part-6-site-local-addresses-and-link-local-addresses/