[QUESTION] What is the best license option for new files introduced in QEMU?

[Aleksandar Markovic]

I read LICENSE file, but I read also recent contributions, and it is
not clear to me what version of GPL is best/recommended for new file
just being introduced to QEMU:

* GPL 2.0
* GPL 2.0 (or later at your option)
* GPL 2.1
* GPL 2.1 (or later at your option)

or something else. (The rest od wording of license preamble is clear
to me.) Please somebody explsin snd clarify.

Thanks,
Aleksandar