1. Stacks are data structures which can be added to or removed from at one end only. Suppose you have a stack called 

 stack stack1; 

that already contains 10 elements, and you wish to retrieve the third element in it; that is, the third element pushed onto the stack. 

A. What sequence of operations must be done in order to obtain this element? 

a. Use the pop operation (stack1.pop()) seven times, followed by the push operation (stack1.push())

b. Use the top operation (stack1.top()) seven times, followed by the pop command (stack1.pop())

c. Use the pop operation (stack1.pop()) seven times, followed by the top command (stack1.top())

d. All of the above are correct

Answer: _____________

Explain your choice for part A (i.e. what is happening in the sequence of operations):