What is the minimum number of carbon atoms required for an alkane to contain a quaternary carbon atom?

In which of the following substances is the carbon atom arranged in a regular tetrahedral structure?

The reactions which produce alcohol as the product are:
$A$. $CH_{4} + O_{2} \xrightarrow{Mo_{2}O_{3}}$
$B$. $2CH_{3}CH_{3} + 3O_{2} \xrightarrow[\Delta]{(CH_{3}COO)_{2}Mn}$
$C$. $(CH_{3})_{3}CH \xrightarrow{KMnO_{4}}$
$D$. $2CH_{4} + O_{2} \xrightarrow{Cu/523 \ K/100 \ atm.}$
$E$. $CH_{3}CH=CHCH_{3} \xrightarrow{KMnO_{4}/H^{+}}$
Choose the correct answer from the options given below:

In the dichlorination reaction of propane,a mixture of products is obtained. How many isomers does the mixture contain?

The $B.P.$ of branched-chain alkanes as compared to straight-chain alkanes is:

In alkanes,the bond angle is $...^o$.