Final answer:
Parallel simulation is the audit technique that requires the most technical expertise on the part of an auditor.
Step-by-step explanation:
Parallel simulation is the audit technique that is likely to require the most technical expertise on the part of an auditor. It involves running a copy of the client's system in parallel and comparing the results of both systems to identify any discrepancies. This technique requires a deep understanding of the client's systems and the ability to accurately simulate their operations.