What does this sign mean?
A)It warns that there may be ice on the road.
B)That in case of fog you cannot exceed the indicated speed.Correct
C)That you are approaching a foggy area.
The sign in the question indicates the prohibition of driving at a speed higher than that indicated on the sign, only in the case where the circumstances indicated by the lower complementary panel apply, that is, in case of fog. There are also panels for rain and snow.