Which of the following audit techniques would BEST aid an auditor in determining whether there have been
unauthorized program changes since the last authorized program update?

A.
Test data run

B.
Code review

C.
Automated code comparison

D.
Review of code migration procedures

Explanation:
An automated code comparison is the process of comparing two versions of the same program to determine
whether the two correspond. It is an efficient technique because it is an automated procedure. Test data runs
permit the auditor to verify the processing of preselected transactions, but provide no evidence about
unexercised portions of a program. Code review is the process of reading program source code listings to
determine whether the code contains potential errors or inefficient statements.A code review can be used as a
means of code comparison but it is inefficient. The review of code migration procedures would not detect
program changes.