Correct Answer - b
The correct numbering of parent chain is
`overset(1)(C)H_(2)=overset(2)(C)H-overset(3)(C)H_(2)-overset(4)(C)H_(2)-overset(5)(C)-=CH`
Double and triple bond are equidistant from terminals, numbering is done in alphabetical order, giving lower number to ene.
Hence, `C_(2)-C_(3)` are `sp^(2)-sp^(3)` hybridised.