What do oxygen (o) and bromine (br) have in common?

The choices can be found elsewhere and as follows:

They both tend to gain electrons to gain stability.

They both have seven valence electrons.

They are both halogens.

They are both unreactive.

I believe the correct answer is the third option. Ox ygen (o) and bromine (br) do have something in common that would be they are both halogens. Hope this answers the question.