Web-based software usually requires additional layers, called _____, to communicate with existing software and legacy systems.?

Explain in what circumstances penetrate-and-patch is a useful program maintenance strategy.

What will be an ideal response?

The code for implementing the String pop() operation is

A stack based on a linked list is based on the following code ``` class Node { String element; Node next; Node(String el, Node n) { element = el; next = n; } } Node top = null; ``` A) if (top != null) { top = top.next; String el = top.element; return el; } else throw new RuntimeException("Empty Stack"); B) if (top != null) { String el = top.element; top = top.next; return el; } else throw new RuntimeException("Empty Stack"); C) if (top != null) { String el = top.element; top = null; return el; } else throw new RuntimeException("Empty Stack"); D) return top.element; top = top.next;