What is the primary function of the `reduce()` method?

The reduce() method is designed to execute a specified function on each element of an array, reducing the array to a single cumulative value. This function takes two parameters: an accumulator, which accumulates the callback's return values, and the current value being processed in the array.

As it iterates over the elements, reduce() allows you to perform operations such as summing numbers, concatenating strings, or building complex data structures, ultimately resulting in a single output value. This makes it particularly useful for operations that require aggregation, such as summing values or merging data, as you can carry forward intermediate results easily.

The other options describe different functionalities that do not align with the essence of what reduce() accomplishes; creating a new array, sorting an array, and transforming elements could be achieved by methods like map(), filter(), and sort(), but these are distinct from the cumulative operation facilitated by reduce().