`NH_3` has got pyramidal structure. By replacement of `H` atom it forms `(CH_3)_3 N` and `(SiH_3)_3 N` molecules which are found to have different geometries.
Which is the correct relation of bond angles ?
A. `NH_3 gt (CH_3)_3 N gt (SiH_3)_3 N`
B. `(SiH_3)_3 N gt (CH_3)_3 N gt NH_3`
C. `NH_3 gt (SiH_3)_3 N gt (CH_3)_3 N`
D. `(CH_3)_3 N gt (SiH_3)_3 N gt NH_3`