I can't select "Armature" when adding a Track To constraint So, after adding a track to constraint to the bone that will follow the eye bone, I try to select "Armature" but when I click it, it wont add it to the "Target:" field.  Furthermore, I noticed that it says "Add Object Contraint".  It should say "Add Bone Constraint".  Please refer to the photo below.  I want to make the "Armature" option appear in the field after I click it and I want to make sure that above, it says "Add Bone Constraint".  Can someone help me?  Thanks!
You've clicked on the Object Constraints tab, where you could give a constraint to the whole armature, it's not what you want, what you want is the Bone Constraints. To have access to this tab you need to switch to Pose mode, select your bone, click on the right tab.