In presence of organic peroxide, the halogen adds with the carbon in double bond having greater number of hydrogen atom.(antimarkovnikov addition) It is called "Kharash Effect or, Peroxide effect".
\(\mathrm{CH}_2=\mathrm{CH}-\left(\mathrm{CH}_2\right)_2 \mathrm{COOH} \xrightarrow{\mathrm{HBr}} \mathrm{BrCH}_2 \mathrm{CH}_2\left(\mathrm{CH}_2\right)_5 \mathrm{COOH}\)
hence, Option D is a correct answer.
${C_2}{H_2}\xrightarrow{{{O_3}}}X\xrightarrow{{Zn/C{H_3}COOH}}Y$
$\begin{array}{*{20}{c}}
{C{H_3}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_3}\,\,\,\,\,\,\,} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,} \\
{\mathop C\limits_7 {H_3} - \mathop C\limits_6 - \mathop C\limits_5 H = \mathop C\limits_4 H - \mathop C\limits_3 H - \mathop C\limits_2 \equiv \mathop C\limits_1 H} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{C{H_3}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}$
જે નીચેના ક્રમમાં છે.