Final answer:
Boats over 9 meters up to 12 meters must have lifejackets, a bailer, and a sound signaling device as safety equipment.
Step-by-step explanation:
The safety equipment required for boats over 9 meters up to 12 meters includes not just lifejackets but additional items to ensure the safety of individuals on board. According to standard safety regulations, such boats must be equipped with the following items:
- Lifejackets for each person on board to provide flotation in the event of capsizing or falling overboard.
- A bailer to remove water that may enter the boat.
- A sound signaling device, such as a whistle or horn, to signal for help or communicate with other vessels.
Therefore, the correct answer is 'd. Lifejackets, a bailer, and a sound signaling device.'