Which statement is true about utilizing a data network for voice traffic? Select the best response.

A.
Adding bandwidth to the data network is the primary solution to provide for the needs of voice traffic.

B.
Because voice traffic volume cannot be calculated, network bandwidth requirements must be determined from an existing installation.

C.
Voice traffic will require some form of QoS mechanisms in most networks.

D.
Voice traffic will require some form of QoS implementation only in congested networks.

E.
Network congestion must be totally eliminated to provide proper voice traffic performance.