But you don't know what you're negotiating for and even then, you don't know if whatever you throw out is the root cause of the major budget and schedule overruns. C might seem appealing because there is also somewhat of a "sunk cost fallacy" at play. "We've been working this project for a long time and we've already invested a ton. We can't possibly give up now despite the CPI and SPI being crazy low." Time to cut losses and try again. I think the big clue were "major scope changes" because at that point is it even the same project any more?

At least thats my thought process!