"Who are you?"
This sentence might be interpreted in singular too. There should be a mark (plural) in front of it.
i.e: Ki vagy te.
you are right, and in addition to that the formal versions shall be also accepted: "Ki Ön?" (sing.) "Kik Önök?" (pl.)
yes this is one of many examples i keep on interpreting as singular and get wrong
"Ki ön?" was correct for me. The English sentence does not specify, so in translating it, it could be either.
"Kik vagytok?" if you ask multiple people, "Ki vagy?" for a single person.
"Kik Önök?" if you ask multiple strangers/bosses/elders, "Ki Ön?" for a single one.
In the lesson there is no hint for using plural. So also the singular translation is correct. It would be better to mark that plural should be used to practice this.
kik is plural -- if you are asking several people who they are, you need the plural kik in Hungarian.
So it should be "Ki ön" but "Ki önök"? I'm just making sure since I've never seen kik before.