Kaylee and Nicholas, two audit staff associates are working on an audit of JayTee Industries, Inc., a national provider of golf and dune buggies across the United States. Kaylee asks Nicholas if the auditors typically make any assumptions pertaining to a client's system of internal control. Which of the following represents Nicholas' best response to this question?

a.) The external auditors typically assess control risk at its lowest at the beginning of the audit, and adjust accordingly as the audit progresses.

b.) The external auditors typically rely on the results of previous years audits and/or professional experience and judgment in forming a preliminary opinion on a client's system of internal control.

c.) Generally accepted auditing standards require the external auditors to assess control risk at its highest level at the beginning of the audit, and make subsequent adjustments as necessary.

d.) Internal control is typically tested by the internal audit function more so than the external auditors, as they are more familiar with areas of high risk in the client's operations.