Final answer:
The most reliable evidence for an auditor comes from external sources combined with more effective internal controls, making Option C the correct answer.
Step-by-step explanation:
The question presented is related to the field of auditing, specifically the evaluation of the reliability of evidence. Auditors must assess the effectiveness of a company's internal controls when deciding on the reliability of the evidence they gather. The most reliable evidence typically comes from external sources when the effectiveness of internal control is high. Therefore, among the given options:
- Option C: source of evidence - external effectiveness of internal control - more effective, would provide the auditor with the most reliable evidence.
When evaluating evidence from external sources, the effectiveness of internal controls plays a pivotal role in increasing the reliability of that evidence because external sources are less likely to be influenced by the company's internal biases or errors. In contrast, internal sources of evidence are often considered less reliable due to the potential of internal manipulation or bias, especially when the effectiveness of internal controls is low.