What defines an array?

An array is defined as a collection of elements of the same type, which makes the second choice the correct answer. This definition is fundamental to understanding how arrays work in programming. Arrays are designed to store multiple items of a specific data type together, allowing for efficient access and manipulation of the collection as a single entity.

When you create an array, you specify the type of data it will hold—such as integers, characters, or floats—and all elements within that array must conform to this type. This homogeneity allows for fixed-size allocation in memory, meaning that the system knows how much space is required for the array, improving efficiency in data processing.

The other choices may describe different structures or concepts: a sequence of mixed data types refers more to lists or tuples in certain programming languages, not arrays; a structure for dynamic memory allocation is indicative of dynamic data structures (like linked lists or hash tables) that can grow and shrink in size; and a linked set of nodes describes linked lists, which operate very differently from arrays by using pointers to connect elements scattered in memory. Understanding how arrays differ fundamentally from these other structures is crucial for any programmer.