8. A graph traversal is the act of interrogating (or visiting) every node in the graph. Traversals are useful when nodes are added to a tree in a certain order (perhaps random) and retrieved in some other given order. Three frequently used traversals, preorder,inorder, and postorder, are shown in the diagram below, with diagram a illustrating a preorder traversal, b an inorder traversal, and c a postorder traversal.

a) Rearrange the tree above so that a preorder traversal will print the node key values in alphabetical order. Change only the key values in the nodes. Do the same for an in-order traversal.

b) Perform the other two traversals on both of the trees redrawn in Part a.