What best describes the live migration of a virtual machine from one host to another?

What best describes the live migration of a virtual machine from one host to another?
A . It requires shutting down the virtual machine before migration
B . It requires that the I/O and CPU calls be quiesced to ensure that as the CPU and memory state of a VM is able to be transferred between hosts without interruption of services
C . It requires that the filesystem of the virtual machine be migrated to the new host before the state can be
D . The virtual machine will be unavailable for a few seconds while it is suspended, transferred and then reinstated

Answer: B