could the answer not read "which is the origin" if there were two to choose from? Thanks.
"Nombre" = first name. The people talking have the same first name. So don't get confused later and think "nombre" is a person's last name (surname). Because duolingo has such a sentence and you will get it wrong ha.
To say it in advance, English is not my native language. So could you translate the sentence to "What is our name's origin?"?
As far as I know, "cual" never means when, you would use "cuando" for when. Cual means what or which.
I'm definitely no Spanish expert though, so I might be wrong.