Which amongst the following is incorrect statement?

(A) `` O _{2}^{+} `` ion is diamagnetic.
(B)The bond orders of `` O _{2}^{+}, O _{2}, O _{2}^{-} `` and `` O _{2}^{2-} `` are `` 2.5,2,1.5 `` and `` 1 `` , respectively.
(C) `` C _{2} `` molecule has four electrons in its two degenerate `` \pi `` molecular orbitals.
(D) `` H _{2}^{+} `` ion has one electron.