Which steps are required to repair the cluster when the old Leader is brought back online?

In a 3-node auto-failover cluster, the Leader has been brought down for patching that lasts longer than the configured TTL. A Standby has been promoted.

Which steps are required to repair the cluster when the old Leader is brought back online?
A . On the new Leader, generate a Standby seed for the old Leader node and add it to the cluster member list.
Rebuild the old Leader as a new Standby and then re-enroll the node to the cluster.
B . Generate a Standby seed for the newly promoted Leader.
Stop and remove the container on the new Leader, then rebuild it as a new Standby. Re-enroll the Standby to the cluster and re-base replication of the 3rd Standby back to the old Leader.
C . Generate standby seeds for the newly-promoted Leader and the 3rd Standby Stop and remove the containers and then rebuild them as new Standbys.
On both new Standbys, re-enroll the node to the cluster.
D . On the new Leader, generate a Standby seed for the old Leader node and re-upload the auto-failover policy in “replace” mode.
Rebuild the old Leader as a new Standby, then re-enroll the node to the cluster.

Answer: A