What is required in order to change lanes without causing any disturbance or risk?

The driver should only verify that he gives a signal with the winker while changing lanes.

The driver should give a signal with the winker and with the headlights while changing lanes.

The driver should communicate with other drivers and give a signal 3km before changing lanes.

The driver should give a timely signal from a sufficient distance, perform a peripheral check in all directions, and glance at the mirrors, before starting to change lanes.