I agree you might wish to try a D cup. A lot of women say they aren’t a certain bra size, but they are. So I know it might be hard for you to wrap your head around being a D cup. But you should try on a D cup and you might be surprised at how comfortable it feels, how good you look at it, and how completely you fill the cups, especially after you have done the scoop and scoop.
Also, looks like your breasts may be fairly firm, so most likely mammary gland as well as fatty tissue.
You have full female breasts like a woman and you need those womanly breasts of yours to be in a bra, like a woman.