The order of appearance of the following with rising temperature during the refining of crude oil is:

$A$ hydrocarbon with molecular formula $C_4H_6$ undergoes the following reactions:
$A$. Decolourises molecular bromine.
$B$. Reacts with $HBr$.
$C$. Addition of ozone and then cleavage of the ozonide by $Zn / H_2O$ gives the product $C_4H_6O_2$.
Then,the structure of the hydrocarbon is:

Which of the following will give a mixture of $cis$ and $trans-1,4-$dimethylcyclohexane upon catalytic hydrogenation?

Action of hydrogen chloride on $CH_3-C(CH_3)=CH_2$ and on $CH \equiv CH$ will predominantly give the compounds,respectively:

$Ph-CH_2-C\equiv N$ $\xrightarrow[THF]{LDA}$ $\xrightarrow{CH_3I} 71\%;$ The end product of this reaction will be:

Write chemical equations for the combustion reaction of the following hydrocarbons:
$(i)$ Pentene
$(ii)$ Hexyne
$(iii)$ Toluene