In which of the following molecules / ions (${\text{BF}}_3,{\text{NO}}_2^{-},{\text{NH}}_2^{-}$ and ${\text{H}}_2\text{O}$), the central atom is $s{p}^2$ hybridized?

1. ${\text{BF}}_3$: Boron has $3$ valence electrons, forms $3$ $\sigma$ bonds. $s{p}^2$ hybridized.2. ${\text{NO}}_2^{-}$: Nitrogen has $5$ valence electrons $+1$ from charge. Forms $2$ $\sigma$ bonds and has $1$ lone pair. Total steric number $=3\Rightarrow s{p}^2$ hybridized.3. ${\text{NH}}_2^{-}$: Nitrogen forms $2$ $\sigma$ bonds and has $2$ lone pairs. Steric number $=4\Rightarrow s{p}^3$.4. ${\text{H}}_2\text{O}$: Oxygen forms $2$ $\sigma$ bonds and has $2$ lone pairs. Steric number $=4\Rightarrow s{p}^3$.