Which of the following is not a linear data structure?

A binary tree stores data in a branching hierarchy, so it is not a linear structure.

An array lays elements in a single sequence, making it linear.

A queue arranges items one after another, so it is linear.

A stack keeps elements in a single ordered pile, also linear.

Linear structures place elements one after the next, unlike a tree.

Add-on: graphs are another common non linear data structure.