What is the VMware recommended best practice to scale vCloud Director cells?

A. Deploy N+1 cells where N is number of resource groups or n/3000 + 1 powered on virtual machines.

B. Deploy one vCloud Director Cell per 3000 simultaneous client connections.

C. Deploy one additional vCloud Director Cell per N where N = Virtual Machines / Resource Pools * Number of vCenters.

D. Deploy a one to one ratio of vCloud Director Cells per vCenter cluster.

Reference: https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/vcat/vmware-architecting-a-vcloud-director-solution.pdf (19)