What additional requirement is placed on riders of mopeds?

Answer: B — Must wear a helmet

Riders of mopeds are required to wear a helmet to enhance their safety while operating the vehicle. This requirement is in place because mopeds, while generally slower than motorcycles, still pose significant risks in terms of accidents and injuries. Helmets provide vital protection for the head, reducing the severity of injuries in the event of a crash. The requirement is particularly crucial given that moped riders are often more vulnerable on the road than those in enclosed vehicles. Helmets help mitigate the potentially life-threatening consequences of accidents by minimizing impact forces during falls or collisions. The other options indicated do not reflect mandatory requirements for moped riders under North Carolina law. While wearing a reflective vest could enhance visibility, it is not a formal requirement for moped operation. Similarly, carrying a first-aid kit or having a passenger registration are not established prerequisites for riders of mopeds.