Trace an initially empty Stack (called S) through the following operations:

Stack S = new Stack();

S.push(new Integer(4));

S.push(new Integer(5));

//a) What is the content of the stack at this point?

Integer Y = S.pop();

S.push(new Integer(9));

S.push(new Integer(1));

S.push(new Integer(7));

S.push(new Integer(2));

//b) What is the content of the stack at this point?

Integer Y = S.pop();

S.push(new Integer(8));

S.push(new Integer(6));

//c) What is the content of the stack at this point?