Answer (A) is correct . Firewalls separate an internal network from an external network (such as the Internet) and prevent passage of specific types of traffic.
Answer (B) is incorrect because Mapping involves monitoring the execution of an application program to determine certain statistical information about a computer run.
Answer (C) is incorrect because Parallel simulation involves the use of specially prepared application-type programs to process transactions that have also been run in routine processing.
Answer (D) is incorrect because Concurrency controls manage situations in which two or more programs attempt to use a file or database at the same time.
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