Splay tree deletion. In the solution, I understand that you need to move to the 9 to the ROOT before removing it. But, in step 5, why is the value 10 moved to the top? How is it determined that 10 will be the new root?

7. (20 points) Given the following splay tree, what would the tree look like after the deletion of 9 using a normal splay. (You may wish to write intermediate tree(s) to ensure partial credit. Rather than copying parts of the tree that remain the same from the previous intermediate tree, you may simply use dashed lines from the appropriate node to indicate that either the ancestors or descendants remain the same from the previous intermediate tree. However, your final tree must be complete, and not use any dashed lines.) 13 14 10 12 10 12 10 510 14 2 13 10 12 12 14 12 1