And that’s precisely where bra “sister sizes,” a.k.a. an alternate, but close size that may give you a better fit, come into play. For example, maybe you get your measurements: 34D.
Basically, the actual breast size of bra measuring 32C is identical to a 34B and it’s the same for a 32B and a 34A. Are you starting to see the correlation here? You take it backward too, with a 36C ...