单项选择题
Data encryption and decryption occurs at which layer of the OSI model?（）
A.Transport B.Presentation C.Session D.Application
单项选择题 Which of the following is the MOST accurate description of a L2/L3 switch?（）
单项选择题 A technician would use a physical network diagram to determine:（）
单项选择题 Which of the following uses PKI?（）
