Question

question 4 which ipv6 network prefix is only intended for local links and can not be routed? fc00::/7 2001::/3 fe80::/10 ff00::/12

Explanation:

The IPv6 prefix FE80::/10 is used for link - local addresses. These addresses are only valid on the local link and are not routed across different networks. FC00::/7 is used for unique local addresses which are not meant to be globally routed but are different from link - local. 2001::/3 is for global unicast addresses which are routed globally. FF00::/12 is for multicast addresses.

Answer:

FE80::/10