Which of the following is NOT a key characteristic of a linked implementation of stacks?

a$.$ A linked implementation allows the stack size to grow or shrink dynamically as elements are pushed onto or popped from the stack:

b$.$ Elements in the stack are stored as nodes in a linked list. Each node contains the data element and a reference $($or pointer$)$ to the next node in the stack.

c$.$ When an element is pushed onto the stack, a new node is created to hold the element, and it becomes the new top of the stack. The new node's reference points to the previous top node.

$$ d$.$ Linked implementation of stacks have a constant space overhead as they do not need to allocate memory for pointers.