What is the best case complexity for traversals in a balanced tree?

In a balanced tree, the best case scenario for traversals, such as in-order, pre-order, or post-order traversals, involves visiting every node in the tree once. Since the traversal requires accessing each node to visit and process it, the time complexity for this operation is directly proportional to the number of nodes in the tree.

For a balanced tree with 'n' nodes, irrespective of the tree's height, the traversal will require O(n) time because each node must be examined at least once. Therefore, the correct complexity is O(n), as this reflects the need to visit all nodes within the tree rather than just a subset of them. Conversely, complexities like O(1), O(log n), and O(n log n) do not accurately represent the nature of tree traversals, as they imply constant, logarithmic, or hybrid time efficiency rather than the exhaustive nature of a full traversal.