Identify the lowest energy lewis structure for nitrogen oxide

Below attachment shows the four possible lewis structures of Nitrogen Oxide (Nitrous Oxide).

              Among given Lewis structures, Structure-C has the lowest energy.

Explanation:
                     The greater the stability of any compound the lesser will be its energy. Among different Lewis structures of N₂O or any other compound, the one which comprises of less number of formal charges will be having lesser energy. I have selected structure-C but not Structure-B (as both have same number of formal charges) because in structure-C oxygen has a formal charge of -1. Being more electronegative oxygen tends to attract electrons toward itself. While, in structure-B one of the Nitrogen atom is having -1 charge which is not feasible and makes the structure energetically high.

Note:
        Formula for calculating formal charge is as follow,

Formal Charge  =  # of Valence e⁻s - [e⁻s in lone pairs + 1/2 bonding e⁻s]

Answer; carbon monoxide (co);