Final answer:
When a rule needs to be explained and all captains are on the bench, the referee should ask a captain or alternate to come off the bench or select a player on the ice to communicate the rule interpretation.
Step-by-step explanation:
If there is a question of rule interpretation in a game and the Referee needs to explain the rule to the Captain, but all the designated captains are not available on the ice, the referee should ask for the captain or an alternate captain to step off the bench to discuss the rule. If all designated captains are unavailable, the referee might choose a player currently on the ice to relay the information, ensuring that the team's leadership is aware of the rule interpretation.
This maintains the flow of the game while respecting the communication protocols established by the sport's governing body.