What is an array in C++?

An array in C++ is a collection of variables all of the same type, allowing them to be accessed using an index. Each element in the array is stored in contiguous memory locations, making it efficient to access and manipulate them. The index of an array typically starts at zero, which means the first element can be accessed with the index [0], the second with [1], and so forth. This structure is particularly useful for handling a fixed-size sequence of elements, such as lists of numbers or strings.

The other options do not accurately capture the essence of what an array is. An array does not consist of variables of different types, nor is it only a data structure that stores a single value; rather, it encompasses multiple values. Additionally, an array is not simply a set of predefined values, as its elements can be modified and assigned new values during runtime, making it dynamic in that respect.