Final answer:
The achieved (actual) level of audit risk cannot be known with certainty and is affected by various factors.
Step-by-step explanation:
The achieved (actual) level of audit risk cannot be known with certainty. It is Option 3 from the given choices. This is because audit risk is affected by various factors, such as the nature of the business being audited, the complexity of the financial statements, and the extent of audit procedures performed. While auditors assess and mitigate audit risk to the best of their ability, there is always a level of uncertainty involved.