According to MO theory which of the list ranks the oxygen species in terms of increasing bond order
O₂²⁻,O₂⁺, O₂⁻,O₂²⁻,
a. O₂²⁻, O₂⁻, O₂⁺, O₂
b.O₂⁺, O₂, O₂⁻, O₂²⁻
c.O₂, O₂, O₂⁺, O₂²⁻
d.O₂²⁻, O₂⁻, O₂, O₂⁺