单项选择题 You plan to give an on-site presentation. The external display available for your audience is a 42-inch flat panel monitor. You need to ensure that the presentation on the monitor of your computer is duplicated on the external monitor for the audience. What should you do?（）

单项选择题 You connect your computer to a multimedia projector. When you play a video, you cannot hear the audio. You n eed to ensure that the projector provides audio and video playback. What should you do?（）

单项选择题 You install a third-party application on your computer. The application uses port 80 to negotiate a listening port. After establishing the listening port, the application uses dynamic ports above 6000. You need to configure Microsoft Windows Firewall to allow traffic for the application. What should you do?（）