The correct option is C 5
If d(X, Y) is the distance between points X and Y then
d(X, Y)=X - Y (if X > Y) =Y - X (if X < Y)
In the given question point D is 4 and point H is -1.
As D > H, d(D, H) = D - H = 4 - (-1) = 5
∴ distance between point D and point H, d(D, H) = 5.