What is the function of the turn signal flasher relay in a motorcycle's lighting circuit?

1. It automatically interrupts the current flow to the turn signal bulbs, causing them to flash on and off at a controlled rate.
2. It increases the voltage to the indicator bulbs to make them brighter than the brake lights.
3. It prevents the turn signals from operating if the headlight is turned off.
4. It acts as a fuse that disconnects the indicators during a short circuit.