The network team is planning to implement IPv6 on the company's existing IPv4 network infrastructure. The network currently uses IS-IS to share routes between peers. Which task must the team perform so that IS-IS will run in multitopology mode on the updated IPv6 network?
To run IS-IS in multitopology mode on an IPv6 network, the network routers must be configured to use metric-style wide. This configuration is necessary because the TLVs (Type-Length-Values) used to advertise IPv6 information in link-state packets (LSPs) use extended metrics, which require the use of the wide metric style.
When multitopology support for IPv6 is used, use the metric-style widecommand to configure IS-IS to use new-style TLVs because TLVs used to advertise IPv6 information in link-state packets (LSPs) are defined to use only extended metrics.
B seems the correct option
i would go for B. metric-type wide is mandatory!
metric is optional os mentioned on config guide: The optional isis ipv6 metric command allows you to differentiate between link costs for IPv6 and IPv4 traffic when operating in multitopology mode.
B https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_isis/configuration/15-mt/irs-15-mt-book/ip6-route-multi-isis.html#:~:text=multiple%20topology%20mode.-,IS%2DIS%20Multitopology%20Support%20for%20IPv6,-IS%2DIS%20multitopology