Refer to the exhibit. The debug output of an IKEv2 exchange between two devices is shown. Why is the IKEv2 exchange failing?

The IKEv2 keyring stores pre-shared keys indexed by peer address or hostname, not the peer identities used for profile matching; a missing key would produce a distinct pre-shared-key authentication error rather than the profile-matching failure shown.

If UDP 500 packets were being dropped, no IKE messages would arrive at the device at all and the debug output would show no exchange activity rather than a failure mid-exchange.

Choice C is textually identical to choice D in this question, making it a duplicate entry rather than a distinct incorrect option.

The IKEv2 profile uses identity matching to verify remote peers during the IKE_AUTH exchange. If the remote peer's identity (IP address, FQDN, or email) is not present in the server's IKEv2 profile, the router cannot associate the incoming session with a valid profile and the authentication phase fails. Adding the identity to the profile resolves the mismatch visible in the debug output.