Anoperatorjustcompletedarepairtoadisksubsystemthatcontainsadiskheartbeat.Beforereturningthesystembackintoproductionmode，thereisarequirementtoverifythediskheartbeatisfunctioning.Howshouldtheoperatordetermineifthediskheartbeatnetworkfunctioning？（）
A.Usetheclinfocommandtomonitorthediskheartbeat
B.UsethemailcommandtocheckformessagesformHACMP
C.Usethedhbreadcommandtoverifythediskheartbeatlink
D.Usetheclstatcommandtoverifytheappropriatenetworkconnectionsareavailable