news - which/what/?

[Lenka]

Let’s imagine a dialog between two people:
A: Hey, I’ve got sme good news for you!
B: Really? And what/which/? (are they) ?

=> my question is: how should person B answer, if the person wants to know the news? I guess neither the answer what… and which… is all right.

[Tdol]

What is it? (news- singular)
Which' is used when we have an understood range of possibilities- in your example, I don't know.

[Lenka]

Yes, but when we say "some news" we mean some kind of news, don't we? And if we say "some KIND" than we must ask: "which (kind) is it", don't we?

[Tdol]

You want to know what the news was (the facts), not the type (you already know- good)