4) Solve the following problems: 9 (b) 1. Apply the DFS based topological sort algorithm to the graph on the left; Your DFS traversal will start with vertext a. Write down the nodes visited during a regular DFS traversal. Write down the nodes popped by the stack during this traversal. Write down the final topological order for this graph. 2. Run the source based removal algorithm on the graph on the right. Explain teh steps of the algorithm and how you arrive at the final topological order.