Definitely more of a B for me. Although I only let it drop to one bar. I don't like to be on Empty but I also don't like going to the gas station.
I'm probably more of a "B" but only because I don't pay enough attention and my older son also drives my car, so I'll get in the car when it's pretty low, but I wont' have time to fill up, so... I'll make it to where I'm going and deal with it later. Good thing I only live a quarter mile from work.