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

• Correct answer
  A

  $\mathrm{BF}_3$ and $\mathrm{NO}_2^{-}$
• B

  $\mathrm{NO}_2^{-}$and $\mathrm{NH}_2$
• C

  $\mathrm{NH}_2^{-}$and $\mathrm{H}_2 \mathrm{O}$,
• D

  $\mathrm{NO}_2^{-}$and $\mathrm{H}_2 \mathrm{O}$

Hence, the correct answer is option: 'A'.