[Adam]

Rule 10-4-4
Essentially, no one may stand at the bench (with exceptions specifically listed) except the head coach (per 10-5-1a). Without the use of the box, the HC is granted extra exceptions to stand and request a TO or to replace a player who has been directed to leave the game.

The HC is the only coach acknowledged in the rule book. There's nothing that says ACs can't ask questions, and most of us will answer legitimate questions from an AC.

No one, however, is allowed by rule to attempt to influence an official's decision or disrespectfully address an official. Sometimes, we give a little extra rope to the HC, but don't confuse this with what's allowed by rule.