What technique is used to prevent eavesdropping of digital cellular telephone conversations?

A.
Encryption

B.
Authentication

C.
Call detail suppression

D.
Time-division multiplexing

Explanation:
The name “TDMA”( Time Division Multiple Access) is also used to refer to a specific
second generation mobile phone standard – more properly referred to as IS-136, which uses the
TDMA technique to timeshare the bandwidth of the carrier wave. It provides between 3 to 6 times
the capacity of its predecessor AMPS, and also improved security and privacy. In the United
States, for example, AT&T Wireless uses the IS-136 TDMA standard. Prior to the introduction of
IS-136, there was another TDMA North American digital cellular standard called IS-54(which was
also referred to just as “TDMA”).