Identify the incorrect statement.

Assertion $(A)$: The maximum covalency of $Si$ and $Ge$ is $6$ but that of carbon is $4$.
Reason $(R)$: Due to the presence of $d$-orbitals in $Si$ and $Ge$,both these elements can undergo $sp^3d^2$ hybridisation and covalency of $6$ is possible. Carbon has no $d$-orbitals in it and hence its covalency is $4$.
The correct answer is:

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{P}_4O_6 + H_2O \longrightarrow H_3PO_3$

Choose the acidic oxide from the following.

The number of non-ionisable protons present in the product $B$ obtained from the following reaction is:
$3C_{2}H_{5}OH + PCl_{3} \rightarrow 3C_{2}H_{5}Cl + H_{3}PO_{3} (A)$
$H_{3}PO_{3} + PCl_{3} \rightarrow H_{4}P_{2}O_{5} (B) + HCl$

Carbon differs from other elements of the group. Which is the false statement?