单项选择题 A consulting firm is locating 30 consultants at a client site for a nine-month project. What need does the firm have that can be met by a wireless solution? （）

单项选择题 Which IP telephony component provides call processing, such as signaling, that in a traditional voice network is provided by switching equipment, such as a PBX?（）

单项选择题 Which software-based security threat is typically spread from user to user via e-mail?（）