When is it most appropriate to use the guest OS strategy rather than the service console strategy to back to VMs?

You work as a administrator at Domain.com. You are trying to decide whether to back up virtual machines (VMs) using a backup agent in each guest OS or using a backup agent in the service console. When is it most appropriate to use the guest OS strategy rather than the service console strategy to back to VMs? Select two

A.
when space for storing backups is severely limited

B.
when all of the VMs must operate 24 hours a day, 7 days a week

C.
when the current backup software license is per server and is very costly

D.
when quick recovery of full systems is a priority