Refer to the exhibit. Which configuration must be applied for the TACACS+ server to grant access-level rights to remote users?

The `aaa accounting commands 15 default start-stop group tacacs+` command is used for logging the commands executed by users to the TACACS+ server, not for authorizing or granting specific access-level rights.

The `aaa authentication login enable` command configures authentication for entering enable mode, but it does not define the access-level rights or authorized commands for a user after they have logged in.

The command `aaa authorization exec default group tacacs+` configures the router to use the TACACS+ server for authorizing user access to the EXEC shell. This allows the TACACS+ server to define what privilege level or specific commands an authenticated remote user is permitted to execute, thereby granting access-level rights.

The `aaa authorization exec default local if-authenticated` command instructs the router to use its local user database for EXEC authorization if the user has been successfully authenticated, rather than consulting a TACACS+ server for authorization.