单选题Which statement regarding 802.1X is true?（）A 802.1X is simple to implement on any workstation.B 802.1X requires access-lists to allow IP voice traffic across.C Authentication is initiated when the workstation connects to an Ethernet port.D 802.1X requi

 They are evaluated by all the three WHEN clauses regardless of the results of the evaluation of any other WHEN clause.

 They are evaluated by the first WHEN clause. If the condition is true， then the row would be evaluated by the subsequent WHEN clauses.

 They are evaluated by the first WHEN clause. If the condition is false， then the row would be evaluated by the subsequent WHEN clauses.

 The INSERT statement would give an error because the ELSE clause is not present for support in case none of the WHEN clauses are true.

displays only the list of default values

displays only the list of all basic parameters

displays the currently in effect parameter values

displays only the list of all advanced parameters

displays the list of all the parameter files of a database

 TACACS+ is the only supported authentication server type.

 If a host initiates the authentication process and does not receive a response， it assumes it is  not authorized.

 RADIUS is the only supported authentication server type.

 Before transmitting data， an 802.1x host must determine the authorization state of the switch.

 Hosts are required to havea 802.1x authentication client or utilize PPPoE.

 None of the other alternatives apply.

No logging is enabled by default.

By default, the information is stored in a file named events.

Only the message severity level must be configured.

You can configure the router to send log messages to the console.

There are five phases of IKE negotiation.

There are two phases of IKE negotiation.

IPsec VPN tunnels are not supported on SRX Series devices.

IPsec VPNs require a tunnel PIC in SRX Series devices.

 It returns versions of rows only within a transaction.

 It can be used in subqueries contained only in a SELECT statement.

 It will return an error if the undo retention time is less than the lower bound time or SCN specified.

 It retrieves all versions including the deleted as well as subsequently reinserted versions of the rows.

The cranes may be operated independently

The cranes may be interconnected for twin operation

When twinned，the crane rotation on the foundation assembly is unlimited

All of the above

NAT is not supported on SRX Series devices.

NAT requires special hardware on SRX Series devices.

NAT is processed in the control plane.

NAT is processed in the data plane.

You cannot assign an interface to a functional zone.

You can specifiy a functional zone in a security policy.

Security zones must have a scheduler applied.

You can use a security zone for traffic destined for the device itself.

No logging is enabled by default

By default the information is stored in all file named events

Only the message severity level must be configured

You can configure the router to send log messages to the console

Synonyms can be created only for a table 

Synonyms are used to reference only those tables that are owned by another user 

A public synonym and a private synonym can exist with the same name for the same table 

The DROP SYNONYM statement removes the synonym, and the table on which the synonym has been created becomes invalid

It can have a maximum of five expressions in a list 

It returns the highest NOT NULL value in the list for all rows 

It requires that all expressions in the list must be of the same data type 

It requires that at least one of the expressions in the list must have a NOT NULL value