2. (16 pts.) Linearization Run the DFS-based topological ordering algorithm on the following graph. When- ever you have a choice of vertices to explore, always pick the one that is alphabetically first. E H (a) Indicate the pre and post numbers of the nodes. (b) What are the sources and sinks of the graphs? (e) What linearization is found by the algorithm? (d) How many linearizations does this graph have