. Which data structure is used for implementing recursion?a) Stackb) Queuec) Listd) Array

Analysis of the Options

1. Option a: Stack

   • Stacks are Last In First Out (LIFO) data structures. They are particularly well-suited for recursion because they can keep track of function calls and local variables when a function calls itself. Each recursive call pushes a new frame onto the stack, and when the base case is reached, the function starts to return, popping frames off the stack.

2. Option b: Queue

   • Queues are First In First Out (FIFO) data structures. They are primarily used for scenarios where order matters, like in breadth-first search, but they are not suitable for implementing recursion.

3. Option c: List

   • Lists can store elements in a sequential manner but do not inherently manage the function call states like a stack does. Therefore, while lists can be used to hold data that a recursive function may process, they don't facilitate recursion itself.

4. Option d: Array

   • Arrays are fixed-size data structures used for storing fixed-length sequences of elements. Like lists, they do not provide the necessary functionality for managing recursive function calls.

Conclusion

Based on the analysis, the data structure that is utilized for implementing recursion is the Stack. This is due to its ability to manage function calls and handle the push and pop operations that occur during recursive processes.

Final Answer

a) Stack