Q15A. Consider the graph with the following vertices and edges:
V = {a, b, c, d, e, f}
E = {{a, b}, {a, c}, {a, d}, {a, f}, {b, c}, {b, f}, {c, d}, {c, f}, {d, e}, {d, f}}
Which of the following sets of edges represent subgraphs of the graph that are spanning trees? (Select all that apply.)
{{a, b}, {a, c}, {a, d}, {a, f}, {d, e}}
{{a, d}, {b, c}, {c, d}, {d, e}, {d, f}}
{{a, b}, {a, c}, {a, d}, {a, f}, {d, e}, {d, f}}
{{a, c}, {a, d}, {d, e}, {d, f}}
{{a, b}, {a, c}, {a, d}, {a, f}}
