What methodology is least disruptive and will retain the file system structure, configuration, data, and DNS information?

There is a need to carry out a tech refresh of a PowerScale cluster. Old nodes must be removed because they will soon be at end of service life.

What methodology is least disruptive and will retain the file system structure, configuration, data, and DNS information?
A . Add the new nodes to the cluster and use SmartPools to move the data to the new nodes
B . Install the new nodes into the cluster and migrate using a host-based utility
C . Install the new nodes as a new cluster and use SyncIQ to replicate the data to the new nodes
D . Install new nodes into the cluster and use SyncIQ to replicate the data from the old to the new nodes

Answer: A