Explanation : In Kruskal’s Algorithm we choose on edge of G
which has smallest weight among the edges of G.
So (b, e) = 2, (e, f) = 3, (b, c) = 4, (a, c)= 8, (f,g) = 4
(c,d) = 5
Alternately
Order the edges in non-decreasing order and pick
edge one by one until all the nodes are completed
with no edge making cycle on addition.