Give recursive algorithms that perform preorder and postorder tree walks in θ(n) time on a tree of n nodes.

a) Preorder: Left, Right, Root; Postorder: Left, Right, Root
b) Preorder: Root, Left, Right; Postorder: Left, Right, Root
c) Preorder: Left, Root, Right; Postorder: Right, Left, Root
d) Preorder: Root, Right, Left; Postorder: Root, Left, Right