Which of the following best describes the relationship between trees and graphs?

The choice that indicates a tree is a specific type of graph without cycles is accurate because it captures the fundamental properties that define a tree within the context of graph theory. A tree is characterized as a connected graph that has no cycles, meaning that there is exactly one path between any two nodes. This lack of cycles differentiates trees from more general graphs, which may include cycles and can have various structures, such as disconnected components or non-hierarchical arrangements.

In addition to being acyclic and connected, trees inherently have a hierarchical structure, where nodes can have parent-child relationships. This is a key aspect that simplifies many algorithms and operations, such as searching and traversing. Understanding this classification helps clarify the distinction between different types of data structures and their applications in algorithms, leading to more effective problem-solving approaches.

By recognizing that all trees are graphs, specifically acyclic connected graphs, it becomes evident that the correct answer aligns with the definitions and properties of these data structures.