What is the base case in recursion?

The definition of the base case in recursion is fundamental to understanding how recursive functions operate. In recursion, a base case serves as the termination condition that prevents the function from calling itself indefinitely. This is crucial because, without a clear base case, the function would continue to make recursive calls, potentially leading to a stack overflow error.

The base case typically specifies a condition under which the recursive function can provide a direct answer without making further recursive calls. For example, in a function designed to calculate the factorial of a number, the base case might be when the input number is 0 or 1, at which point the function would return 1 instead of calling itself again.

The other options do not accurately describe the base case. The maximum number of recursive calls allowed does not represent a base case but rather a limiting factor; the first case to be handled in a recursive function might be part of the process but is not the definition of a base case; and the initial value passed does not determine when a function stops making recursive calls. Therefore, the correct identification of the base case as the condition under which a recursive function stops calling itself is key to successfully implementing recursion.