Final answer:
Auditing by testing the input and output of a computer system instead of the computer program itself will option a:not detect program errors which do not show up in the output sampled.
Step-by-step explanation:
When auditing a computer system, testing the input and output is a common method used. This approach focuses on evaluating the accuracy and reliability of the data that enters and exits the system, rather than analyzing the computer program itself. While this method provides auditors with valuable evidence, it may not detect program errors that don't manifest in the sampled output, meaning option A is correct.
This is because the errors might occur within the program's logic or processing, which may not directly impact the output being tested.