A person may not act as a crew member of a civil aircraft if alcoholic beverages have been consumed by that person within the preceding:

The correct choice is based on regulations set forth by aviation authorities that govern the operation of civil aircraft. According to the Federal Aviation Administration (FAA) regulations, there is a restriction known as the "bottle to throttle" rule. This rule states that no person may act as a crewmember of a civil aircraft within 8 hours of consuming alcoholic beverages. This timeframe is intended to ensure that all crew members are sufficiently sober and capable of safely performing their duties, thus promoting the safety of flight operations.

It is important to acknowledge that while some might assume longer periods might be beneficial for safety, the regulation is specifically instituted to impose a reasonable limit that balances the need for readiness and safety. Therefore, the 8-hour restriction is designed to protect both the crew and passengers by ensuring that crewmembers have adequately cleared alcohol from their systems before they take on the responsibility of operating an aircraft.