Which of the following reactants will give same product with HBr in presence and absence of peroxide ?

Which of the following compounds form the same product with HBr in presence and absence of peroxide-

C_(4)H_(16) has isomers with the following properties: (a). Gives same product with HBr in the presence or absence of peroxide (b). Gives tertiary alkyl halide with HX (c). Does not contain C=C bond (d). Does not form geometrical isomer but has C=C bond. Identify the isomers.

The alkene that will give the same product with HBr in the presence as well as in the presence of peroxide is

The alkene that will give the same product with HBr in the absence as well as in the presence of peroxide is