In data structures and algorithms,traversalrefers to systematicallyvisiting nodesin a tree or graph in order to process them. “Visiting” typically means performing some operation at each node, such as reading its value, marking it as seen, computing a property, or collecting it into an output structure. Traversal is foundational because many algorithms—search, path finding, connectivity checks, topological analysis, and evaluation of expressions—are built on traversal patterns.

Intrees, traversal has classic forms: preorder, inorder, and postorder depth-first traversals, as well as breadth-first traversal (level-order). Each defines a rule for the order in which nodes are visited relative to their children. Ingraphs, traversal must additionally handle the possibility of cycles and multiple paths; textbooks therefore emphasize maintaining a “visited” set to avoid infinite loops. The two principal graph traversal strategies areDepth-First Search (DFS)andBreadth-First Search (BFS). DFS explores along a path as far as possible before backtracking, while BFS explores layer by layer outward from a start node.

Options A, B, and C do not define traversal. Changing values may happen during traversal, but it is not what traversal means. Removing all nodes is deletion, not traversal. Connecting all nodes is not a standard traversal concept. The correct definition is the process of visiting all nodes (typically reachable from a starting node, or all nodes in the structure if fully connected).