Which action would you take to convert a high availability over LAN deployment to high availability over WAN?

Which action would you take to convert a high availability over LAN deployment to high
availability over WAN?

A.
Reinstall second Cisco Unified CCX node and add it to cluster over WAN.

B.
Apply a ”Warm Standby” license.

C.
Apply a ”WAN Standby” license.

D.
Do a fresh installation of the whole system as high availability over WAN.