单项选择题 Several users report that they are unable to print to a new printer recently installed. The technician is unable to ping the printer. Which of the following is the MOST likely cause?（）

单项选择题 A technician plugs a USB device into the front panel of a desktop computer and nothing happens.The technician knows that plug-n-play is enabled. Which of the following BEST describes a possible cause to this issue?（）

单项选择题 Which of the following commands will be run at a command prompt to determine which WindowsOS is running on the computer?（）