If a Binary Search Tree Becomes Unbalanced After an Element

Multiple Choice

If a binary search tree becomes unbalanced after an element is added, it is sometimes possible to efficiently rebalance the tree by ___________________ .

A) using left and right rotations
B) selecting a leaf node to use as a new root
C) reconstructing the tree from scratch
D) all of the above
E) it is impossible to rebalance a tree efficiently