What programming concept involves a function calling itself to repeat execution under a condition?

• A. Iteration
• B. Memoization
• C. Recursion
• D. Inheritance

Answer: (C)

Recursion is the idea of a function calling itself to solve smaller instances of the same problem, continuing this self-call pattern under a condition until a base case is reached. Each recursive call works on a simpler input, and the base case provides a clear stop to prevent infinite work. This approach fits problems that can be broken into similar subproblems, such as calculating factorials or traversing tree structures. For example, a factorial function calls itself with a smaller number until it reaches 1, at which point it returns a simple value and the results combine on the way back up the call chain. While iteration uses loops to repeat work, recursion achieves repetition by self-invocation. Memoization can accompany recursion to cache results and avoid repeated work, and inheritance relates to object-oriented design for sharing behavior between classes, not to repeating execution via self-calls. Also keep in mind that each recursive call adds a layer to the call stack, so deep recursion can risk stack overflow if there isn’t a proper base case or tail-call optimization.