Stack
A stack is a linear data structure that follows the LIFO (Last-In-First-Out) principle. It is a collection of elements where an element can be inserted or removed only from one end known as the top of the stack. The element that is inserted last is the first one to be removed.

Operations on Stack
Stack supports two main operations:
1. Push: Adds an element to the top of the stack.
2. Pop: Removes the top element from the stack.

Implementation of Stack
There are several ways to implement a stack, but two common methods are using an array or a linked list.

Array Implementation
In the array implementation of a stack, a fixed-size array is used to store the elements. The top of the stack is represented by an index variable that points to the current top element. The push operation involves incrementing the top index and inserting the element at that position. The pop operation involves removing the element at the top index and decrementing the top index.

Linked List Implementation
In the linked list implementation of a stack, a linked list is used to store the elements. Each node in the linked list contains the element and a pointer to the next node. The top of the stack is represented by the head of the linked list. The push operation involves creating a new node with the element and updating the head to point to the new node. The pop operation involves removing the head node and updating the head to point to the next node.

Advantages of a Stack
- Simple and efficient data structure.
- Supports constant-time operations for push and pop.
- Can be used to solve problems involving recursion, backtracking, and parsing.

Applications of a Stack
- Function call stack in programming languages.
- Undo/redo functionality in text editors.
- Balancing of symbols in expressions.
- Depth-first search in graph traversal.

Therefore, the correct answer is option 'B', Stack.