What happens if the sidestick takeover button is held for more than 40 seconds?

If the sidestick takeover button is held for more than 40 seconds, the other sidestick will be latched. This means that the aircraft's flight control system recognizes a prolonged input from one sidestick, indicating that the pilot wants to take control of the aircraft, leading to the latching of the opposing sidestick to prevent conflicting inputs. This feature is part of the system designed to maintain flight safety and ensure that only one pilot actively controls the aircraft, which is crucial during critical phases of flight.

The other options relate to different functionalities of the aircraft systems. However, the primary and intended effect of holding the takeover button for an extended duration focuses on maintaining clear command authority within the cockpit, which is why latching the opposing sidelock is considered the correct answer.