External auditors are most likely to be concerned about the quality of the user-interface design in an information system because:

a. Most behavioral problems arise with information systems as a result of poor design of the user interface

b. There is a high correlation between the quality of the user interface and the level of inherent risk associated with the audit

c. The quality of the user interface affects the extent to which users are likely to make errors when they enter data into the system

d. Controls in the user interface are among the most difficult to test to determine whether they are operating reliably