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

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,what is the bond order of C₂⁺?

A) 1
B) 1.5
C) 2
D) 2.5
E) 3