Mastering Java 2026 – 400 Free Practice Questions to Pass the 'Thinking in Java' Exam

An array is used to represent key information in hashing because it is able to generate a unique index for each key, allowing for constant time lookup and insertion of key-value pairs. The other options, such as linked lists, binary search trees, and stacks, do not have the same efficient lookup and insertion times and do not provide a unique index for each key. Linked lists have linear time lookup, binary search trees have log time lookup, and stacks do not provide a key-value pair structure. Therefore, an array is the most suitable data structure for efficiently representing key information in hashing.