Yep, it’s B, supposedly sold without a markup, although I’m sure someone must be making some money. They do limit the number of author copies to 1000 (per year I guess? Haven’t checked), so that people don’t just abuse that and sell all outside of Amazon.
B & C look the same from outside, of course. You’re not paying retail printing prices, but they might eke out a couple pennies of profit.
For customer sales, the royalty is 60% minus the print fee. The minimum retail price is 5/3 the author price, and still gives the author nothing.