$SiCl_4$ on hydrolysis forms '$X$' and $HCl$. Compound '$X$' loses water at $1000^{\circ} C$ and gives '$Y$'. Compounds '$X$' and '$Y$' respectively are:

• A
  $H_2SiCl_6, SiO_2$
• B
  $H_4SiO_4, Si$
• C
  $SiO_2, Si$
• D
  $H_4SiO_4, SiO_2$