Debug Command for Incorrect WPA PSK

C.

The best debug command to use when suspecting that a client will not connect to an autonomous AP because of an incorrect WPA PSK is option C, "debug dot11 station connection failure".

This debug command will provide detailed information about the reason for the connection failure, including any authentication or encryption issues. The debug output will show the AP's attempts to connect to the client, any error messages generated during the connection process, and information about the client's association request.

Option A, "debug dot11 mgmt station," provides information about the management frames exchanged between the client and the AP, but may not provide specific information about authentication or encryption failures.

Option B, "debug dot11 aaa authenticator process," provides information about the AAA process, which is used to authenticate clients, but may not provide specific information about encryption failures.

Option D, "debug dot11 encryption," provides information about encryption-related issues, but may not provide specific information about authentication or connection failures.

In summary, the "debug dot11 station connection failure" command is the best option to use when troubleshooting connectivity issues related to WPA PSK authentication on an autonomous AP.