Which of the following does not belong to the same homologous series?

Which of the following does no belong to same group ?

Which of thr following pairs belong to the same homologous series ?

Which of the following belong to the same homologous series? C_(3)C_(8),C_(4)H_(8),C_(3)H_(6)

Which of the following belong to the same homologous series? C_(3)H_(8),C_(4)H_(8),C_(4)H_(6),C_(3)H_(6) .

Give reasons for the following: Isomers belonging to the same homologous series may differ in physical properties but not in chemical properties.