help me graph theory

Exercise 4 (10 points) 1. Are the following graphs Eulerian (have an Euler circuit): complete graph Ks, complete bipartite R3.4. 2. For which value of n. m the following graphs are Eulerian: K, C (cycle graph with n vertices), complete bipartite K, 3. Is there some Euler circuit in G1, G2, G3, G4 presented in Figure 2? (Justify or draw down the circuits). 4. Is there a Hamiltonian circuit in G2 and G4 presented in Figure 2? (Justify or draw down the circuits) 5. Write down the complement graph of G2 and G4 presented in Figure 2. G4 Figure 2: Exercise 4