Mary,

Absent is wrong though this horse is designated the most successful horse on some webpages. The most successful horse has won four gold medals and two more making it more successful than absent.

The Smarts were unknown to me but look like correct responses. My father son pair did the same as these two but in a different sport.

Gerevich is correct: the only winner of gold at six different Olympic Games! Karpati has won six golds but at 'only' four different games. Gerevich and Karpati have been together in the for some decades more or less invincible Hungarian sabre team. K. Pal is another member of that team who has won five successive golds making Hungary one of two nations with two athletes having won gold at five different games.

Wolfgang