Which of the following is an example of a recursive algorithm?

A recursive algorithm is one where a function calls itself in order to solve a problem. The example of factorial calculation is a classic instance of recursion, as it can be defined in terms of itself: the factorial of a number ( n ) (denoted as ( n! )) can be expressed as ( n ) multiplied by the factorial of ( n-1 ) (i.e., ( n! = n \times (n-1)! )), with a base case defined for ( 0! ) which equals ( 1 ).

This self-referential nature of factorial calculation allows it to be implemented using a simple recursive function that keeps reducing the problem size until it reaches the base case. Such recursive algorithms often make the implementation cleaner and easier to understand, as they break complex problems into simpler subproblems.

In contrast, other options like bubble sort and linear search are typically implemented using iterative approaches rather than recursive ones. While binary search can be efficiently implemented using recursion, it primarily emphasizes divide-and-conquer strategies rather than pure recursion itself when considered in algorithm analysis. Thus, the factorial calculation stands out clearly as a quintessential example of recursion in programming.