21. An example of an analog communication method is

A. laser beam
B. microwave
C. voice grade telephone line
D. All of the above
E. None of the above

22. Which of the following layer protocols are responsible for user and the application program support such as passwords, resource sharing, file transfer and network management?

A. Layer 7 protocols
B. Layer 6 protocols
C. Layer 5 protocols
D. Layer 4 protocols
E. None of the above

23. What frequency range is used for FM radio transmission?

A. Very Low Frequency : 3 kHz to 30. kHz
B. Low Frequency: 30 kHz to 300 kHz
C. High Frequency : 3 MHz to 30 MHz
D. Very High Frequency: 30 MHz to 300 MHz
E. None of the above

24. Transmission of computerized data from one location to another is called

A. data transfer
B. data flow
C. data communication
D. data management
E. None of the above

25. Compared to analog signals, digital signals

A. allow faster transmission
B. are more accurate
C. both (a) and (b)
D. All of the above
E. None of the above