Final answer:
In a linked list version of a stack, one typically maintains only a reference to the head, as stacks operate on a Last In, First Out basis and all operations are conducted at the head of the list.
Step-by-step explanation:
In a stack implemented using a linked list, typically only a reference to the head of the list is maintained. This is because stacks adhere to a Last In, First Out (LIFO) principle, which means that items are added and removed from the top of the stack. The head of the linked list represents this top element. There is usually no need to keep a reference to the tail because all push and pop operations occur at the head of the list.
When a new element is pushed onto the stack, it becomes the new head of the linked list. Conversely, when an element is popped from the stack, it is removed from the head, and the next element becomes the new head. This operation allows for constant time addition and removal, which is a crucial property of the stack data structure.