Which one of the following is the correct statement?

1. Boric acid is a Lewis acid, not a protonic acid (it accepts ${\text{OH}}^{-}$).2. Beryllium, due to its small size and lack of $d$ -orbitals, typically has a max coordination number of 4.3. Both ${\text{BeCl}}_2$ and ${\text{AlCl}}_3$ form bridged structures (${\text{BeCl}}_2$ is a chain polymer and ${\text{AlCl}}_3$ exists as a dimer ${\text{Al}}_2{\text{Cl}}_6$) in the solid state involving coordinate bonds from chlorine to the metal.4. Inorganic benzene is Borazine (${\text{B}}_3{\text{N}}_3{\text{H}}_6$).