Consider the following statements and choose correct option

(I) The ease of hydrolysis of tetrahalides of silicon follow the order
$\mathrm{S}\mathrm{i}{\mathrm{F}}_4>\mathrm{S}\mathrm{i}\mathrm{C}{\mathrm{l}}_4>\mathrm{S}\mathrm{i}\mathrm{B}{\mathrm{r}}_4>{\mathrm{S}\mathrm{i}\mathrm{I}}_4$

(II) The inductive effect of F dominates over the $\mathrm{\pi }$ backbonding and hence the above order is correct.
 

Correct statements among regarding silicones are:
$\left(a\right)$ They are polymers with hydrophobic character.
$\left(b\right)$ They are biocompatible.
$\left(c\right)$ In general, they have high thermal stability and low dielectric strength.
$\left(d\right)$ Usually, they are resistant to oxidation and used as greases.

Identify the correct statements from the following:

a) Silicones are hydrophobic in nature. 

b) The repeating unit in silicones is

c) In a ${\mathrm{C}}_{60}$ molecule, twenty ${\mathrm{C}}_6$ rings and twelve ${\mathrm{C}}_5$ rings are present. 

d) Dehydration of formic acid by concentrated ${\mathrm{H}}_2{\mathrm{SO}}_4$ at ${100}^o\mathrm{C}$ gives ${\mathrm{CO}}_2$. 

e) The distance between two layers in graphite is $34 \mathrm{pm}$.