a
\(\begin{array}{*{20}{c}} {{\text{H}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\ {|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\ {{\text{H - C - C = C - C}} \equiv {\text{C - H}}} \\ {|\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\;\;\,\,\,\,\,\,\,\,\,\,} \\ {{\text{H}}\,\,\,\,\,\,{\text{H}}\,\,\,\,\,\,{\text{H}}\,\,\,\,\;\;\,\,\,\,\,\,\,\,\,\,\,\,\,} \end{array}\)

Number of sigma bonds \(=10\) 

Number of \(\pi\) -bonds \(=3\)