Amongst the given structures , which are permissible resonance forms ?

Among the given sets, which represents the resonating structures ?

N_2O has a linear, unsymmetrical structure that may be thought of as a hybrid of two resonance forms. If a resonance form must have a satisficatory Lewis structure, which two of the five structures shown below are the two resonance forms of N_2O ?

Which is not a permissible resonating structure ?

Which of the following arrow is used between two structures to indicate that these are resonance forms ?

Which of the following structures represents the best resonance form for the following compound?