Four diatomic species are listed below. Identify the correct order in which the bond order is increasing in them:

1. A
   ${\text{He}}_2^{+}<{\text{O}}_2^{-}<\text{NO}<{\text{C}}_2^{2-}$
2. B
   $\text{NO}<{\text{O}}_2^{-}<{\text{C}}_2^{2-}<{\text{He}}_2^{+}$
3. C
   ${\text{O}}_2^{-}<\text{NO}<{\text{C}}_2^{2-}<{\text{He}}_2^{+}$
4. D
   ${\text{C}}_2^{2-}<{\text{He}}_2^{+}<{\text{O}}_2^{-}<\text{NO}$