A

Step 1: Analyze each species in List-I and determine their bond orders and magnetic properties.
A. N₂ → N₂⁺:
- The bond order of N₂ is 3 (there are three bonds: one sigma and two pi).
- Removing an electron (which is typically from a pi bond) would generally maintain the bond order, but the magnetic property changes (since N₂ is diamagnetic and N₂⁺ is paramagnetic). This matches with (iv).

B. O₂ → O₂²⁺:
- The bond order decreases from 2 to 1. The species tends to lose its paramagnetic property as it transforms into the O₂²⁺, which is diamagnetic. This matches with (ii).

C. B₂ → B₂⁺:
- The bond order increases from 1 (B₂) to 2 (B₂⁺), with no change in magnetic property (both are paramagnetic). This matches with (iii).

D. NO⁻ → NO:
- The bond order is 2 for both, but the addition of an electron results in a transition from paramagnetic to diamagnetic. This matches with (i).

Therefore, the final matching is:
A-(iv), B-(ii), C-(iii), D-(i). Thus, the correct answer is option A.