Final answer:
The correct statement is option 'b', which says that audit procedures used to test and evaluate the design effectiveness of controls might also provide evidence about their operating effectiveness. The other statements are generally incorrect because operating effectiveness and design effectiveness require distinct testing procedures, and a single set of audit procedures is generally not sufficient for both.
Step-by-step explanation:
The correctness of the statements provided in the question can be assessed based on audit standards and practices. Specifically, the question pertains to evaluating the effectiveness of controls within an organization's processes or systems. In auditing, controls are measures put in place to ensure the reliability of financial reporting and compliance with applicable laws and regulations. When auditing the design effectiveness of controls, auditors look at whether control procedures, if operated as designed, would be expected to prevent or detect and correct material misstatements. In doing so, they may also gather some evidence on whether the controls are being consistently applied as intended, thus providing insight into their operating effectiveness.
Statements 'a' and 'c' are generally incorrect. Evidence about the operating effectiveness of controls should be based on procedures specific to testing how those controls perform over time, not solely on design tests. Also, while there may be some overlap in the audit procedures used to test design and operating effectiveness, each requires specific considerations and thus a set audit procedures may not be applicable for both. An example illustrating the concept could involve verifying how well a company's procedure for approving expenditures is working in practice (operating effectiveness) versus merely assessing whether the approval process, as designed, is logical and should theoretically work (design effectiveness).