In 2002, Congress passed the Sarbanes-Oxley Act. With the enactment of this legislature, accountants and auditors' work changed because it

a.required that internal accountants co-develop an internal control system with their external auditors

b.expanded the opportunities for auditors to engage in consulting activities with their audit clients

c.expanded the scope of the audit beyond financial information

d.required that auditors report on the effectiveness of an organization's system of internal control