Problem 1 (10 points) Give all minimum spanning trees for the following graph. The edgelist of the graph, listing the edges only from the earlier nodes to the later ones, with the weights in parentheses, is a : b(1), f(2), g(6) b:c(1),d(2), e(4) c: e(4) d: e(2), f(1) e: f(2), g(1)