Which of the following pairs of ions is isoelectronic and isostructural?

1. ${\text{CO}}_3^{2-}$: Total electrons $=6+(3\times 8)+2=32$. Shape: Trigonal planar.2. ${\text{NO}}_3^{-}$: Total electrons $=7+(3\times 8)+1=32$. Shape: Trigonal planar.Since they have the same number of valence electrons and the same structure, they are isoelectronic and isostructural.(Note: ${\text{ClO}}_3^{-}$ and ${\text{SO}}_3^{2-}$ are also isoelectronic and both are pyramidal, making Option A also potentially correct, but B is the most standard textbook example).