Your task is to ask the right question.
You will be shown a post to StackExchange that is incomplete: that is, in order to provide a useful solution to this post, the original poster needs to provide some additional information.
In order to elicit that additional information from the original poster, you want to ask a question.
You will be provided a list of ten possible questions that you can ask. You must provide two pieces of information:
Which of these questions is the single best one? If you could only ask one question, which one would you ask?
Which other questions would be valid to ask, even if not best. You should use this as sparingly as possible and only mark the ones that really would be valid questions to pose to the original poster.
The interface will force you to choose a single best question by marking it with a radio button, and other valid questions with check boxes.
Some of these are really hard. Try your best to answer them. It took us several minutes per example, so don't rush.
After every question you'll be asked for your confidence in your selection of the "best" question. For some of them you may just have to take an educated guess, for others you will be quite sure.
N.B.: "Best" by definition is also "Valid": so whatever you select as "best" you should also mark as "valid".