According to the law in Ontario, what are motorcyclists and passengers required to wear?

Answer: D — Wear officially certified motorcycle helmets. The helmet chin-strap must be securely fastened.

In Ontario, the law mandates that both motorcyclists and passengers must wear officially certified motorcycle helmets, and it is crucial that the helmet chin-strap is securely fastened while riding. This requirement is in place to ensure the safety of riders and their passengers, as helmets are designed to absorb impact energy during accidents and significantly reduce the risk of severe head injuries. Wearing a properly certified helmet means that the helmet meets specific safety standards designed to provide maximum protection. The necessity of having the chin-strap fastened is equally important because it ensures that the helmet remains securely in place during a ride, providing optimal protection in the event of an accident. Other options, while they may pertain to safety in some way, do not reflect the legal requirements regarding safety gear for motorcyclists in Ontario. For instance, while brightly-coloured apparel can enhance visibility, it is not mandated by law. Similarly, carrying a tool kit, while perhaps useful for roadside emergencies, is not a legal requirement. Stopping driving at night does not pertain to safety gear regulations at all. Thus, the emphasis on wearing a certified helmet is fundamental for legal compliance and rider safety in Ontario.