Which of the following is electron-deficient?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : Boric acid is a weak acid.
Reason $R$ : Boric acid is not able to release $H^{+}$ ion on its own. It receives $OH^{-}$ ion from water and releases $H^{+}$ ion.
In the light of the above statements,choose the most appropriate answer from the options given below.

$A$. What are silicones? State the uses of silicones.
$B$. What are boranes? Give chemical equation for the preparation of diborane.

The incorrect statement regarding '$X$' in the given reaction is $BF_3 + LiAlH_4 \xrightarrow{\text{Ether}} (X) + LiF + AlF_3$.

In which of the following reactions is hydrogen one of the products?
$i$. $2NaBH_4 + I_2 \longrightarrow$
$ii$. $2BF_3 + 6NaH \xrightarrow{450 \ K}$
$iii$. $4BF_3 + 3LiAlH_4 \longrightarrow$
$iv$. $3B_2H_6 + 6NH_3 \xrightarrow{\text{heat}} 2B_3N_3H_6 + 12H_2$

The bonding in diborane $(B_2H_6)$ can be described by