How should a federation be configured when a primary ECS VDC already exists?

How should a federation be configured when a primary ECS VDC already exists?
A . First configure the secondary ECS as standalone and then add the VDC to the federation.
B . First create the storage pool on the secondary ECS and then configure it on the primary ECS of the federation.
C . First get the VDC access key from the primary ECS of the federation and then add it to the secondary VDC
D . Add the secondary VDC to the federation during fabric and HAL installation.

Answer: B