单项选择题 Users are unable to access the Internet but the users are able to send/receive email from theirdesktops. Which of the following ports is MOST likely being blocked?（）

单项选择题 When testing a CAT5 cable, the technician notices that pin A is open. However, the cable stillworks fine. Which of the following describes how this is possible?（）

单项选择题 Which of the following allows a WAP to be installed in a location where there are no power outletsavailable?（）