Which of the following conversions involves change in both shape and hybridisation?

(A) Both ${\mathrm{CH}}_4$ and ${\mathrm{C}}_2{\mathrm{H}}_6$ have ${\mathrm{sp}}^3$ hybridization and tetrahedral shape.
(B) Both ${\mathrm{NH}}_3$ and ${\mathrm{NH}}_4^{+}$ have ${\mathrm{sp}}^3$ hybridization. But the shape of ${\mathrm{NH}}_3$ is pyramidal and shape of ${\mathrm{NH}}_4^{+}$ is tetrahedral.
(C) Both ${\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{H}}_3{\mathrm{O}}^{+}$ have ${\mathrm{sp}}^3$ hybridization. ${\mathrm{H}}_2\mathrm{O}$ is bent shaped molecule and ${\mathrm{H}}_3{\mathrm{O}}^{+}$is pyramidal.
(D) ${\mathrm{BF}}_3\to {\mathrm{BF}}_4^{-}$ involves change in both shape and hybridization. ${\mathrm{BF}}_3$ is trigonal planar with ${\mathrm{sp}}^2$ hybridization.
${\mathrm{BF}}_4^{-}$is tetrahedral with ${\mathrm{sp}}^3$ hybridization.

Hence, the correct option is  (D)