Which statement describes the appropriate usage of extension seatbelts?

The appropriate usage of extension seatbelts is best described by the statement regarding their design for infants and oversize passengers. Extension seatbelts are specifically created to accommodate individuals who may not fit comfortably in a standard seatbelt. This includes infants, who may require a different fit due to their size, as well as oversize passengers who may need extra length to secure the seatbelt properly.

By focusing on this function, it highlights the importance of safety and comfort for those individuals who might otherwise be at risk of having their seatbelt be ineffective. It ensures that all passengers, regardless of their size, can be properly secured during a flight. This design consideration is essential in maintaining high safety standards within aviation regulations.

The other statements do not accurately represent the intended use of extension seatbelts. For instance, suggesting that they are only for children misrepresents their purpose, while stating they are optional for regular passengers overlooks the obligation to ensure all passengers are safely secured.