Matching nitrogen oxidation numbers via calculation

Steps:

• In HNO3, assign: H = +1, 3O = -6; for neutrality, N = +5.
• In NF3, 3F = -3; for neutrality, N = +3.
• In NH4+, 4H = +4; for +1 charge, N = -3.
• In NO, O = -2; for neutrality, N = +2.
• In NO2-, 2O = -4; for -1 charge, N = +3.

Why none is correct:

• HNO3 has N at +5; no option matches this value.

Why the others are wrong:

• B: N = -3 (from hydrogen assignments and ion charge).
• C: N = +2 (from oxygen and neutrality).
• D: N = +3 (from oxygens and ion charge).

Final answer: None