How many structures are possible for $${C_5}{H_8}$$  with one triple bond?

Solution :
$${C_5}{H_8}$$  can have the following structure with one triple bond.
$$\mathop {C{H_3} - C{H_2} - C{H_2} - C \equiv CH,}\limits_{{\text{Pent - 1 - yne }}} $$        $$\mathop {C{H_3}C{H_2} - C \equiv C - C{H_3}}\limits_{{\text{Pent - 2 - yne }}} $$
\[\underset{\text{3-Methylbut-I-yne}}{\mathop{C{{H}_{3}}\underset{\begin{smallmatrix} |\,\,\,\,\, \\ C{{H}_{3}}\, \end{smallmatrix}}{\mathop{-CH-}}\,C\equiv CH}}\,\]