Among the following,the correct statement$(s)$ is(are):
$A$. $Al(CH_3)_3$ has the three-centre two-electron $(3c-2e)$ bonds in its dimeric structure.
$B$. $BH_3$ has the three-centre two-electron $(3c-2e)$ bonds in its dimeric structure $(B_2H_6)$.
$C$. $AlCl_3$ has the three-centre two-electron bonds in its dimeric structure.
$D$. The Lewis acidity of $BCl_3$ is greater than that of $AlCl_3$.

• A
  $A, B, C$
• B
  $A, B, D$
• C
  $A, B$
• D
  $A, C$