You are a security administrator for your company. All servers run Windows Server 2003. All client computers run Windows XP Professional. The network is configured as shown in the Network Diagram exhibit. （Click the Exhibit button.）Users in the sales department use portable computers that are not connected to the company network. Each week sales users travel to the company’s main office and connect to the IEEE 802.11b wireless LAN （WLAN）. The WLAN is configured as shown in the Wireless Configuration exhibit. （Click the Exhibit button.） The WLAN hardware does not support IEEE 802.1x. Once a Week， sales users connect to the WLAN to retrieve confidential sales documents from file servers on the network.    You discover that unauthorized users intercepted data in sales documents while the documents were transmitted over the WLAN. You need to protect sales documents from being intercepted by unauthorized users.  What should you do？（）