Frame relay and X.25 networks are part of which of the following?

A.
Circuit-switched services

B.
Cell-switched services

C.
Packet-switched services

D.
Dedicated digital services

Explanation:
Some examples of packet-switching technologies are the Internet, X.25, and frame relay.
Incorrect Answers:
A: X.25, and frame relay are packet switching services, not circuit-switching services.
B: X.25, and frame relay are packet switching services, not cell-switching services.
D: X.25, and frame relay are packet switching services, not dedicated digital services.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 674