I am about to take off for the day, so I am going to give the answer. I don't think you will get this detailed of an AWT question from the exam, but here it is anyways.
Taken from Graphic
Java Mastering the JFC Volume 1:AWT by David Geary
Drawing a rectangle by invoking Graphics.drawRect() results in an extra row of pixels on the right and bottom sides of the rectangle.
So, the drawRect() method adds an extra row of pixels, but the fillRect() method does not. You can see this by doing the drawRect(5,5,10,10) method and then do the fillRect(5,5,10,10) method, but change the color first. You will see that drawRect() acts like a border to the fillRect().
So the answer is D.
Have a good one and I will throw some more out tomorrow.
Bill