@Sage_medics In my opinion, (sorry if I’m replying to my own comment, I don’t have that prime shit or whatever) bone B was designed to hold and give birth to a baby. I might be wrong so someone can correct me.
@Sage_medics I think B is female. I’m not to good at naming specific areas of bone. But the center of the lower pelvis of bone B is much bigger and wider then bone A. Bone A lower pelvis is more smaller and not as wide as B.