What is about a Sprint 0
In many projects you can found a sprint 0 in which the technical infrastructure is build and perhaps the backlog entries get the state Ready.
I didn't find anything about it in the Scrum-Guide. So what is the right answer such a question come in the test?
You can number Sprints however you like in Scrum. Having a Sprint 0 is no more a problem than having a Sprint 1 or even a Sprint -1.
What matters is that each sprint is timeboxed, planned, reviewed, subject to retrospection, and delivers a potentially releasable increment of value to the Product Owner. When people talk about "Sprint Zero" that isn't what they typically mean. Usually "Sprint Zero" is a euphemism for pre-sprint initialization, such as securing resources and getting a backlog in order, and in which no increment of product value is delivered at all. That isn't a genuine sprint, so for examination purposes you should NOT consider "Sprint 0" to be a valid Scrum construct.
Sprint zero is a non-officual term used when starting a new team. Getting an initial backlog in order, getting team space set up with machines for build, for automated testing, getting tooling in place, perhaps some training; a bit of actual work to verify that things work. This is not 'official' Scrum but it is common. We expect teams to be all ready to go after sprint zero to attack the real work.
I agree with you guys. Technically speaking, there is no such thing like Sprint 0. This term is confused with the term “Release 0” . It makes perfect sense to talk about Release 0 as opposed to Sprint 0. For the exam, the correct answer is "no" there is no such thing as Sprint 0.