I'm by no means an expert and I am sure you will get better advice than mine, but here are my thoughts:
The upper right seems to be the worst of the three. By the looks of his face and how he doesn't maintain his mass very far up his horns, I would guess he is a younger billy (maybe 3?).
The upper left looks to be a better goat. Like Schaaf said, however, it is tough to tell. His face looks a bit older and looks like he has a little more mass, but it's just tough to see much. One plus for that goat is that he appears to be alone. Most mature billies will be by themselves.
Of these three, I guess I would probably take the lower left goat. He appears to have the best genetics, but I don't think he is that old since he is with (what I assume) is a group of nannies and kids.
If you are looking for a trophy, I have heard that you want the horns to be about 2 to 2.5 times his ears.
Again, I am sure you will hear from some people that know way more than I do, but just wanted to add my thoughts.