$\begin {array} {1 1} (A)\;\text{Boron $BF_3$ involves $sp^2$ hybridization} \\ (B)\;\text{ $BF_3$ acts as a Lewis acid} \\ (C)\;\text{$BF_3$ is a volatile liquid} \\ (D)\;\text{forms an adduct with $NH_3$} \end {array}$
