$\begin {array} {1 1} (A)\;\text{Boron has high melting and boiling points} \\ (B)\;\text{The hydrides of boron are known as boranes } \\ (C)\;\text{The structure of $B_2H_6$ is $ H_3B - BH_3$} \\ (D)\;\text{In borax , two boron atoms are in triangular geometry and two boron atoms are in tetrahedral geometry} \end {array}$