Boric acid is polymeric due to

In the structure of $B_2H_6$,the number of $BH_2$ groups present in one plane,and the number of $B-H$ terminal bonds,$B-B$ bonds,and $B-H-B$ bridge bonds are respectively:

The stability of $+1$ oxidation state among $Al$,$Ga$,$In$ and $Tl$ increases in the sequence:

Given below are two statements:
Statement $I$: Boron is extremely hard,indicating its high lattice energy.
Statement $II$: Boron has the highest melting and boiling point compared to its other group members.
In the light of the above statements,choose the most appropriate answer from the options given below:

Select the correct statements from the following:
$A$) Aluminium liberates $H_2$ gas with dil. $HCl$ but not with aqueous $NaOH$.
$B$) Formula of sodium metaborate is $Na_3BO_3$.
$C$) Boric acid is a weak monobasic acid.
$D$) For thallium,$+1$ state is more stable than $+3$ state.

Which of the following types of hybridization occurs in diborane $(B_2H_6)$?