John, a VMware Administrator, Has Set a Virtual Machine as Fault

Multiple Choice

John, a VMware administrator, has set a virtual machine as fault tolerant using VMware Fault Tolerance. The fault-tolerant pair of virtual machines worked as expected for several weeks, but for the past two days the fault tolerant pair has been failing over repeatedly. Though there hasn't been an outage, John is concerned. What is a likely cause of the repeated failover?

A) There has been an increased level of VMFS activity.
B) The hosts are at the same patch level.
C) There are only four identical hosts in the vSphere cluster.
D) The virtual machines only have one vCPU.