Give an example of a graph G that is (a) Eulerian but not Hamiltonian. (Explain why G is not Hamiltonian.) (b) Hamiltonian but not Eulerian. (Explain why G is not Eulerian.) (c) Hamiltonian and has an Eulerian trail but is not Eulerian. (d) neither Eulerian nor Hamiltonian, but has an Eulerian trail