Which statement is correct about SDN switches?

All software-defined network (SDN) switches are stateless with respect to their configuration. The configuration is applied from the central controller, and therefore, any configuration contained on the switch does not matter if it is lost during a reboot. Data is not centrally switched at the SDN controller; this would make data transfer too slow and overburden the SDN controller. The data flowing through the switch is not consequential to the SDN controller; some data flows can be stateless, such as UDP, and some can be stateful, such as TCP.