To be honest, A & B, no one wants. It doesn't matter what the field is, those two groups are undesirable and interview process usually weeds them out, but sometimes, the testing can expose them easier. C and D are desirable, but D is optimal as you have said. But in this economy, I would assume you would want C over any others, once the economy gets back on track, D will jump ship because they can, C will be where you will want them to really be, while A and B shouldn't have ever touched day one of job. It is all a matter of what the company is needed and what the learning curve is.
I have applied to quite a few jobs where I have been C, not because I want the job, but I know that I want to grow into the position and work with the company for a while. usually if I feel that i am in the D, I will get bored and search elsewhere. To grow from C to D is optimal for this time period. By the time the economy is better, if you have grown into D from C, you are more likely to stay because of your hard work. That isn't always the case though.