Andrew Lerner, a Gartner analyst, predicted that: a. Although an SD-WAN advantages central manageability and flexible control of the network, a traditional network exceeds the SD-WAN in performance. b. The operation of an SD-WAN can be much less expensive than the operation of a traditional WAN network. c. AN SD-WAN advantages central manageability, flexible network configuration, and better performance of security and bandwidth utilization, but its operating expense would be much higher than a traditional network. d. None of the given choices.