How must a column that is not escorted by emergency vehicles travel so as not to create obstructions for overtaking vehicles?

• 1Travel only in a single file as close as possible to the right edge of the carriageway.
• 2Travel at a speed of no more than 50 km/h.
• 3It must be divided into groups of up to five vehicles each; the following distance between groups must be sufficient for performing an overtake.
• 4Answers 1, 2, and 3.
• 5Answers 1 and 3.