Extent mobility and device mobility both aim to enhance storage utilization and performance. However, what scenario is extent mobility most suitable for?

Extent mobility and device mobility both aim to enhance storage utilization and performance. However, what scenario is extent mobility most suitable for?
A . Large-scale data center relocations
B . Fine-grained data placement and load balancing
C . Rapid, full-device data evacuation
D . Long-term archival storage migration

Answer: B