When network fail-over is enabled, which of the following is true?
A. The fail-over cable status is ignored. Fail-over is determined by the network status only.
B. Either a network failure or loss of voltage across the fail-over cable will cause a fail-over.
C. A network failure will not cause a fail-over as long as there is a voltage across the fail-over cable.
D. The presence or absence of voltage over the fail-over cable takes precedence over network fail-over.