Aluminium is a self-protecting metal,because

Consider the following statements about group $13$ elements:
$A$. $AlCl_3$ achieves stability by forming a dimer.
$B$. $BCl_3$ is an electron-deficient molecule.
$C$. $E^0_{M^{3+}/M^0} \ (V)$ is $+1.26 \ V$ for aluminium.
$D$. In $+1$ oxidation state, thallium is unstable.
The incorrect statements are:

$B(OH)_3 + NaOH \to NaBO_2 + Na[B(OH)_4] + H_2O$
How can this reaction be made to proceed in the forward direction?

Boric acid is solid,whereas $BF_3$ is gas at room temperature because of

The element which has the least metallic character is ..........

Identify the correct statements from the following :
$I$. $Ga_2O_3$ is an amphoteric oxide.
$II$. The dimer of aluminium chloride has three $Al-Cl-Al$ bridge bonds.
$III$. Boron is a very hard refractory solid of high melting temperature.