I go with a) as well, and I add a very generous time allowance on top of my estimate. But you can't really do much when you're told to 'get it done this week'.

I go with a) as well, and I add a very generous time allowance on top of my estimate. But you can't really do much when you're told to 'get it done this week'. First to go out the window is TDD, of course.