On a two-way road, there are no signs or road markings prohibiting a U-turn. When is a U-turn allowed?

A)Never.
B)Whenever you want, because it is always allowed.
C)When they do not endanger other users.Correct
Performing a U-turn is prohibited in any situation that prevents you from verifying that you will not endanger or obstruct other road users, even if there is no express sign, such as on bends and crests of hills with reduced visibility or in case of fog or heavy rain. U-turns are also prohibited at:- Level crossings (it is not prohibited in their vicinity).- Tunnels, underpasses, and sections of road affected by the "Tunnel" sign.- Motorways and dual carriageways, except in places designated for this.- On one-way carriageways and road sections.- On all sections of road where overtaking is prohibited, unless the U-turn is expressly authorised.