Final answer:
Human-powered vessels must have lifejackets, a bailer, and a sound signaling device as essential safety equipment.
Step-by-step explanation:
Human-powered vessels must be equipped with certain safety equipment for a safe boating experience. The correct answer to what equipment is required is d: Lifejackets, a bailer, and a sound signaling device. Lifejackets are essential for personal flotation and safety in the event of an overboard situation. A bailer is used to remove water from inside the vessel if it takes on water, and a sound signaling device is required for communication, especially in cases of emergency or in low-visibility conditions. Having all these items ensures compliance with safety regulations and enhances the chances of survival and rescue if necessary.