Consider the following reaction, $\begin{matrix}
C{{H}_{3}}-CH-CH-C{{H}_{3}}+\overset{\centerdot }{\mathop{B}}\,r \\
|\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
\,\,D\,\,\,\,\,\,\,\,\,C{{H}_{3}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
\end{matrix}$ $\to X + HBr$ Indentify the structure of major poroduct $X$
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