Which of the following statements is true regarding the duties of an SIC?

The correct choice highlights the significant responsibilities of a Second-in-Command (SIC) in ensuring flight safety. An SIC can assume control of the aircraft to prevent or respond to dangerous situations, emphasizing their crucial role during the flight, not just during takeoff and landing. This ability to take command reflects the training and authority bestowed upon SICs, ensuring that they can intervene whenever necessary to preserve the safety of the flight and its occupants.

In contrast, the other options downplay the responsibilities and roles of the SIC. For instance, stating that they are responsible only during takeoff and landing overlooks their ongoing involvement throughout the flight. Mentioning that they must always hand control to another pilot negates their authority in critical scenarios. Lastly, asserting that they are not involved in passenger safety contradicts the fundamental obligations of all flight crew members to ensure the safety and well-being of passengers at all times.