Which of the following alkenes give the same major product with HBr in the dark and with HBr in the presence of peroxide?

Peroxide changes only the regiochemistry. Ethene and cyclohexene are symmetrical, so both ends of the double bond are equivalent and the bromoalkane is the same. 2-Methylpropene and pent-1-ene are unsymmetrical, so the dark reaction gives the Markovnikov bromide while the peroxide reaction gives the primary bromide.