Which feature helps in managing the power consumed by a cluster when virtual machine usage is low?

vMotion is a live migration technology that moves running VMs between hosts without downtime, but it has no capability to monitor power consumption or control host power states.

Dynamic Resource Scheduler (DRS) balances CPU and memory resources across cluster hosts to optimize performance, but it does not make decisions about powering hosts on or off to manage energy consumption.

DPM monitors cluster-wide VM workload levels and, when utilization drops below configured thresholds, uses vMotion to migrate VMs onto a reduced number of hosts and then powers down the now-empty hosts to save energy. When demand rises again, DPM automatically powers standby hosts back on and rebalances the workload. This directly addresses the goal of reducing power consumption during periods of low VM activity.

Storage vMotion migrates live virtual machine disk files between datastores and is completely unrelated to host power management or cluster energy consumption.