When, in order to make a U-turn, you obstruct the movement of vehicles travelling behind you, you must...
A)refrain from doing it and continue on your way.
B)leave the carriageway on the right and wait until conditions allow you to make the manoeuvre.Correct
C)flash the brake light to warn of your manoeuvre.
When remaining on the carriageway, while waiting to perform the manoeuvre, prevents the vehicles travelling behind from continuing, you must leave the carriageway on its right side if possible, until traffic conditions allow the manoeuvre. If it is not possible to pull off to the right, you must abandon the manoeuvre and look for an appropriate place to perform it.