strongly agree with the above counsel: provide your users with a choice of sort-orders ... determined by you, not them ... along with some convenient way to see (as they toggle between the various alternatives ...) what it will do with their list of names. If some customer then contacts you and tells you that they require another option, they can describe it to you and then you can very quickly implement it.
leave this choice to the user, naïvely thinking that no one out there might use it to be an (!) ...