The minimum cost formula can be given as

$$C(x,y) = Max(P) - |f(x) – f(y)|$$

In this case Max(P) = 7 and consider vertical top to bottom approach

A:

C(x,y) = (7 - |1 - 2|) + (7 - |2 - 6|) + (7 - |4 - 3|) = 15

B:

C(x,y) = (7 - |1 - 2|) + (7 - |2 - 6|) + (7 - |6 - 4|) + (7- |3 – 3|) = 21

C:

C(x,y) = (7 - |1 - 2|) + (7 - |2 - 6|) + (7 - |6 - 4|) + (7 - |3 – 6|) + (7 - |4 - 3|) = 24

D:

C(x,y) = (7 - |1 - 2|) + (7 - |2 - 6|) + (7 - |6 - 3|) + (7 - |3 - 3|) = 20

E:

C(x,y) = (7 - |2 - 0|) + (7 - |6 - 4|) + (7 - |3 - 3|) = 17

F:

C(x,y) = (7 - |6 - 2|) + (7 - |2 - 6|) + (7 - |2 - 0|) + (7 - |4 - 3|) = 17

G:

C(x,y) = (7 - |2 - 0|) + (7 - |6 - 2|) + (7 - |2 - 6|) + (7 - |6 - 3|) + (7 - |3 - 3|) = 22

H:

C(x,y) = (7 - |2 - 0|) + (7 - |6 - 4|) + (7 - |3 - 6|) + (7 - |4 - 3|) = 20

From the calculation, the minimum cost for path A. In other words, path A gives the strongest edge.