What does this sign indicate?
A)Obligation to turn left.
B)Prohibition to change direction to the left and also to make a U-turn.Correct
C)Prohibition only to make a U-turn.
The sign in the question indicates the prohibition of changing direction to the left, and therefore also prohibits making a U-turn.
On the other hand, the sign that prohibits making a U-turn does not prohibit changing direction to the left.