I can already say it's not option 1 nor 4 as these go against everything science is. I'd say it's option 3 since it takes a bit and though yes they can be rejected, many scientists build off another individual studying the same material for a lead on where they should look. I hope this works for you and I'm not wrong. It's just that option 3 is most understandable in my mind with common sense of previous schooling.
