Which of the following groups are exempt from seat belt use regulations?

• Passengers in emergency vehicles and in those manufactured before 1964.
• Passengers in buses, rural letter carriers, and children under the age of 8 in taxis and livery vehicles.
• Passengers or operators with a physically disabling condition that prevents them from being restrained.
• All of the above.
  Explanation:

  "Seat belt use is not required in certain emergency vehicles, vehicles manufactured before 1964, by passengers in buses (except school buses, where seat belt use can be mandated by a school district), rural letter carriers during their duties, passengers under the age of eight in taxis and livery vehicles, and individuals with a physically disabling condition that prevents seat belt use, provided a physician certifies this condition."