What is true about Multitrack VxRail cluster expansion?

What is true about Multitrack VxRail cluster expansion?
A . All VxRail networks are routable by default
B . VxRail nodes in the same cluster within a rack can be on different subnets
C . VxRail cluster can be expanded up to a maximum of 4 racks
D . VxRail System VMs run on the nodes in the first rack

Answer: D