Benzoic acid has pKa $4.20$, 2-nitrobenzoic acid $2.17$ and 4-nitrobenzoic acid $3.44$ in water. Which sequence correctly gives decreasing acid strength, and its main reason?

1. A4-nitro $>$ 2-nitro $>$ benzoic; the ortho group is shielded by steric hindrance
2. B2-nitro $>$ 4-nitro $>$ benzoic; the ortho substituent adds the ortho effect to its electron-withdrawing effect
3. Cbenzoic $>$ 4-nitro $>$ 2-nitro; nitro groups donate electrons
4. D2-nitro $>$ benzoic $>$ 4-nitro; the para nitro group is a donor by resonance