I just got a used D3200 for Christmas, and the lens I have for it is the AF Nikkor 50mm f/1.8. I really love it, but for some reason when I go to menu, no matter what I do, the MF/AF section never let's me select it. It is always dull and I can't move the cursor over it. Does this mean that the autofocus is broken on the camera? I don't know what to do!