Assuming that ballooning is possible, under which three circumstances might the VMkernel use a swap

Assuming that ballooning is possible, under which three circumstances might the VMkernel use a swap file for a running virtual machine?

A.
The Mem CtlMaxPercent value is between 10 and 25 percent

B.
Memory cannot be reclaimed quickly enough

C.
The virtual machine is starting up

D.
VMware Tools is not installed

E.
50 percent of the configured memory has already been balooned