What is the termination criteria for recursion?

The termination criteria for recursion is established through the identification of a base case. A base case is a condition that allows the recursive function to stop calling itself. When the function reaches this base case, it can return a value without making further calls, thereby preventing an infinite loop and allowing the function to resolve and unwind back through the chain of recursive calls.

In recursive programming, having a clear and well-defined base case is essential; it serves as a stopping point for the recursion. It ensures that the recursive calls eventually lead to a simple scenario that can be solved directly, thus allowing for completion of the overall recursive operation.

The other options do not accurately reflect the concept of recursion's termination criteria. For example, losing the variable scope does not inherently stop recursion; it may affect variable access but does not determine when recursion ends. Likewise, calling another function does not relate to terminating recursion—it merely indicates that a function is being executed. Finally, reaching a maximum iteration might apply to iterative processes but not specifically to recursion, as recursion relies on conditions to stop rather than prescribed iterations.