How many parents does every node in a tree have?

In a tree data structure, every node, except for the root node, has exactly one parent. This is a fundamental characteristic of trees, which are hierarchical structures. The root is the topmost node and is distinguished by having no parent, making the number of parents for all other nodes consistently equal to one.

This structure ensures that each node has a defined relationship with its parent, which makes it easier to traverse and manage the hierarchical organization. When you move down the tree from the root, the binary relationship of parent to child is maintained. Hence, the correct answer highlights this singular connection between nodes, emphasizing the one-parent rule that governs tree dynamics.

Understanding the parent-child relationship in trees is crucial for various operations, such as traversals, searching, and the maintenance of the hierarchical organization.