If you wish to turn left, you should know that it is prohibited when there is insufficient...
A)a sign expressly authorising the turn.
B)a lane specially designed for making the turn.
C)sufficient visibility.Correct
Turning left normally involves crossing into the oncoming lane; therefore, when there is insufficient visibility (being unable to predict whether vehicles are approaching) it is prohibited to do so even if there is no express sign prohibiting it.
The following sign, no left turn, prohibits making the turn and also changing the direction of travel.
The U-turn prohibited sign prohibits making a U-turn but does allow turning left (provided there is sufficient visibility to do so safely).