$SiO_2$ reacts with

Consider the following reactions:
$Me_3SiCl \xrightarrow{H_2O} A$
$Me_2SiCl_2 \xrightarrow{H_2O} B$
$MeSiCl_3 \xrightarrow{H_2O} C$
$A$,$B$,and $C$ are known as . . . . . . , . . . . . . ,and . . . . . . respectively in silicones formation.

$A$ certain element forms a solid oxide which when dissolved in water forms an acidic solution. The element is:

$C_{60}$ (Buckminsterfullerene) consists of which of the following?

$C_{60}$,an allotrope of carbon,contains:

Element showing the phenomenon of allotropy is