John, the network administrator and he wants to enable the NetFlow feature in Cisco routers...

 To enable NetFlow on a Cisco router interface, the correct command is ip route-cache flow, which is entered in interface configuration mode. This command enables NetFlow switching on the specified interface. NetFlow is a feature that captures IP network traffic as it enters or exits an interface. By analyzing the data provided by NetFlow, a network administrator can determine things like the source and destination of traffic, class of service, and the causes of congestion1.

References: The information provided aligns with the Cisco documentation for configuring NetFlow on Cisco routers, which specifies the command to enable NetFlow on an interface1.