please help, I dont know how to figure it out

6. For NCO-, there are three possible Lewis structures we must investigate: A) IN=C=O I NCO C) NCo Number of valence e- in neutral atom: Number of valence e- when e-given to "e- hog": Charge when e- given to "e- hog": (oxidation state) Number of valence e- when e-evenly split: Charge when when e- evenly split: (formal charge) Based on the primary criterion that formal charge should be as close to zero as possible, which two Lewis structures are better than the third? and Based on the secondary criterion that the more negative formal charge should fall on the more electronegative atom, which Lewis structure is best