Which of the following is a legal requirement for motorcycle helmets in Nova Scotia?

1. They must meet approved safety standards such as DOT, Snell, ECE, or the British Standards Institute (BSI).
2. They are optional if the rider is over 19 years old and has a full license.
3. They must be equipped with a built-in Bluetooth communication system.
4. They are only mandatory on highways with speed limits over 80 km/h.