单项选择题
A. ip communications
B. conferencing
C. customer care
D. telepresence
E. messaging
多项选择题 Which two Internet Protocol (IP) telephony devices are best categorized as infrastructurecomponents?（）
多项选择题 Small businesses face unique customer challenges, which three challenges are small businesseslooking to overcome?（）
单项选择题 What feature does the Partner E-Learning Connection provide?（）