An instruction sign (blue and round)



An information sign (blue and square)


They look almost the same but de meaning is different.

An instruction sign tells you what you have to do. It's obligated to do what the sign says. It's usually round and blue.

An information sign is not connected to an obligation. It just tells you something about the circumstances. Like in this question, it let's you know that further on the road will have one lane less.

In question 7600 the right answer A=information sign but in book it is instruction sign. What is correct and what is the difference between information and instruction sign (like shape)?