Chemical Bonding and Molecular Structure

Consider the following changes I and II
O2−

←

II

O2

→

I

O2+
The correct statements about these changes (I) and (II) in accordance with MO theory are
A) In (I) bond order increases by 0.5 from the existing value
B) In (II) bond order decreases by 1.0 from the existing value
C) In both (I) and (II) magnetic property is not changed
D) In both (I) and (II) magnetic property is changed