Given the resulting list X fromX.add(new Integer(4));X.add(new Integer(7));Object Y = X.fi...

Given the resulting list X from

X.add(new Integer(4));
X.add(new Integer(7));
Object Y = X.first();
X.add(new Integer(3));
X.add(new Integer(2));
X.add(new Integer(5));
Object Y = X.removeLast();
Object Y = X.remove(new Integer(7));
X.add(new Integer(9));

what would be the result of each of the following?

a. X.last();
b. z = X.contains(new Integer(3));
X.first();
c. Y = X.remove(new Integer(2));
X.first();