In which of the following pairs the interatomic bond angle is ${109}^o{28}^{\prime },{120}^o$ respectively?

The correct option is A $N{H}_4^{+},B{F}_3$
a. $N{H}_4^{+}$ has $s{p}^3$ hybridisation and tetrahedral shape so it's bond angle is ${109}^o{28}^{\prime }$ and $B{F}_3$ has $s{p}^2$ hybridisation and planar shape where bond angle is ${120}^o$.
b. $N{H}_3$ has $s{p}^3$ hybridisation and trigonol pyramidal shape so it's bond angle is ${107}^o$.
$B{F}_4^{-}$ has $s{p}^3$ hybridisation and tetrahedral shape where bond angle is ${109}^o{28}^{\prime }$.
c. $N{H}_2^{-}$ has $s{p}^3$ hybridisation and bent shape so it's bond angle is ${104}^o$.
$B{F}_3$ has $s{p}^2$ hybridisation and planar shape where bond angle is ${120}^o$.
Hence correct option is a.