If B-1 has committed five fouls and B-6 enters the game, is it correct for the official to deny A-6 from entering the game after the warning horn?

The correct choice is that A-6 must be allowed to enter the game after the warning horn has sounded. According to basketball rules, once a team has a player who has fouled out, they must substitute a player to take that player's place. In this scenario, since B-1 has committed five fouls, the team must replace B-1 with B-6, who has entered the game.

The rules dictate that if a team is making a substitution due to a player fouling out, the opposing team is allowed to make adjustments or substitutions as well. Therefore, A-6 should be allowed to substitute into the game to ensure fair play and to maintain the flow of the game. This rule is in place to uphold the integrity of game substitutions and ensure that both teams have the opportunity to complete their rotations effectively.