We had a local taxidermist that had several deer aged by their teeth at his shop.He then sent the jaw bone off to the state,only to find out that most were aged wrong by their teeth.
It is hard to tell by the pictures which of these deer are mature,or not mature because they are field dressed.IMO, makes it harder to age them.
I will say that b looks older than the other 2 but but it still looks young for a serious qdm(antler management).BUT,I'm shooting b. 3 1/2 is mature enough for me and I believe b is 3 1/2.
Reason is I am the only 1 that even tries to shoot older deer where I hunt so if I don't shoot a 3 1/2 year old,I may never shoot another deer.