You move from 'very difficult to believe' to 'seems like a very exaggerated version of true events,' which is almost the same thing but from that you directly jump to 'This story is credible' without any middle ground. I am sorry but this seems like a really poor questionnaire design.
Once the poll is made, the answers cannot be edited. The difference was supposed to mean approximately a) I don't believe this could ever happen, b) I believe it can happen exceptionally, but not all the time as the author claims, c) I believe this can be the way system works.
In other words, the second option is like: "I believe that with so many grant proposals, once in a while a crazy thing passes unnoticed; but I don't believe that it happens all the time, not even half of the time -- you have probably seen one or two bad cases, and now you exaggerate to make your case more appealing".
Post will be returning in Main, after a rewrite by the company's writing staff. Citations Galore.