单项选择题
A demarcation point is usually installed and managed by which of the following providers?（）
A. Web host provider B. VoIP company C. Telephone company D. Hardware manufacturer
单项选择题 Prioritizing traffic between data and voice is defined as which of the following?（）
单项选择题 Which of the following LAN technology has a MAXIMUM range of 10,000 meters (6 miles)?（）
单项选择题 Which of the following is the purpose of QoS?（）
