6. Classify the graphs described in parts (a) and (b). Follow your decision with an explanation. (a) The graph shown on the right. (b) A graph with four vertices, all of degree 3 (a) Determine whether the graph shown has an Euler circuit or path. Choose the correct answer below. O A. The graph has both an Euler circuit and an Euler path. O B. The graph has an Euler circuit O C. The graph has an Euler path. O D. The graph has neither an Euler circuit nor an Euler path. O E. There is not enough information to classify the graph. Explain your reasoning. Choose the correct answer below. O A. The graph has all even vertices. O B. The graph has exactly one odd vertex. O C. The graph may or may not be connected. O D. The graph has two vertices with odd degrees. O E. The graph has more even vertices. (b) Determine whether a graph with four vertices, all of degree 3, has an Euler circuit or path. Choose the correct answer below. O A. The graph may or may not have an Euler path. O B. The graph has an Euler path. O C. The graph has an Euler circuit O D. The graph has neither an Euler circuit nor an Euler path. O E. The graph may or may not have an Euler circuit. Explain your reasoning. Choose the best explanation below. O A. All the vertices have odd degrees. O B. The graph has less than two odd vertices. O C. The graph has exactly two vertices with odd degrees. O D. The graph has exactly one odd vertex. O E. The graph is connected