Which of the following are true statements about AVL trees. Select all that apply. There will be a deduction for incorrect selections.

a) Nodes are required to have a minimum number of children to maintain fullness.

b) An AVL tree is also called a height balanced tree

c) For an AVL tree, we need | HLST HRST | = 0 at the root of the tree.

d) If an insertion cause the tree to become unbalanced, a rotation is used to rebalance

e) I can get the data in sorted order by doing a pre-order traversal of the tree.

f) An AVL tree has the search tree characteristic.