A: Rudy Giuliani, who also has the dubious distinction of having the dudeliest staff. Here's the breakdown (via Alas, a Blog):
I know, it's not surprising that Richardson has the largest percentage of Latino staffers, and Obama has the largest percentage of black staffers -- just as it wasn't a shock to learn that the Clinton campaign employs the most women. But nevertheless, it's interesting to see it all laid out in a convenient graph format. --Ann Friedman