Refer to the exhibit. Which of the following is true about this configuration?

The `ip nhrp redirect` command, applied on the hub's tunnel interface, causes the hub to send NHRP redirect messages back to a source spoke when it forwards traffic destined for another spoke, triggering the NHRP resolution process for a direct spoke-to-spoke path. Without this command, spoke-to-spoke shortcuts cannot be initiated by the hub. This is the missing configuration element identified by the exhibit.

Split horizon is an EIGRP or distance-vector routing loop-prevention mechanism and is entirely unrelated to NHRP redirect signaling for spoke-to-spoke tunnel establishment.

IP redirects are ICMP-based messages a router sends to inform a host of a better next-hop, which is a Layer 3 routing function unrelated to NHRP tunnel shortcut initiation.

`ip nhrp shortcut` is configured on spoke routers to install NHRP-resolved shortcut routes into the routing table, not on the hub where `ip nhrp redirect` is the required command.