[shk0690]

The question gives a propyne that reacts with HBr + peroxides, hv to form cis-1-bromopropene
which reacts again with HBr + peroxides to form 1,2-dibromopropane.

I can see why the alkyne forms the cis-1-bromopropene but I am having trouble understanding how the cis-1-bromopropene forms a 1,2-dibromopropane.

There's two options for the radical intermediate for the second bromination.

To form the 1,2-dibromopropane, the first radical intermediate is the correct one, but I don't understand why that is the correct radical intermediate. In radical addition, The Br adds to the less alkyl substituted carbon to form a more stable radical carbon, but this radical intermediate has a secondary carbon radical when it could have formed a tertiary carbon radical.

Also, the question gives a hint that the correct radical intermediate can be explained by resonance stabilization.
Other than radical stabilization of resonance stabilization of allylic radicals, I can't think up a reason how radical intermediate #1 can form due to resonance stabilization.

Any advice/help would be greatly appreciated.
Thank you.
p.s. drawing of radical intermediates attached