Test question

Hi everyone!
Hopefully this is the appropriate thread to post this question in, but I have been struggling with a (seemingly) simple and was wondering if I am on the right track?
The question is:
Out of the following questions regarding a scientific inquiry, which one would be the most appropriate for a research assistant to ask before asking all of the other questions?
1) What has everyone else done in this field?
2) What is the most appropriate method of data collection?
3) Should any sampling procedures be used?
4) Which sort of data source, primary or secondary, should be used?

Thank you for your help!


Less is more. Stay pure. Stay poor.
I always go with 1 when starting a project. AKA a literature reveiw, has the question already been definitively answered, and can we improve upon the current state of knowledge, if not, dont proceed.