Diagram 9-1 the Molecular Orbital Diagram Below May Be Used $\sigma$

Multiple Choice

Diagram 9-1 The molecular orbital diagram below may be used for the following problem(s) .For oxygen and fluorine,the $\sigma$ _2p orbital should be lower in energy than the $\pi$ _2p orbitals.However,the diagram will still yield correct bond order and magnetic behavior for these molecules.
-Refer to Diagram 9-1.According to molecular orbital theory,which of the following species will have the $\underline{\text{ lowest }}$ bond order?

A) B₂⁺
B) Ne₂²⁺
C) C₂⁺
D) O₂²⁺
E) B₂