In a Question Bowl game, a Bonus Question is available exclusively to the team that answered the previous question correctly. The Bonus Questions Open for Ring-In if Controlling Team Answers Incorrectly setting allows you to make Bonus Questions available for other teams to answer them, provided that the controlling (first) team answers it incorrectly:
Check the box next to Bonus Questions Open for Ring-In if Controlling Team Answers Incorrectly to allow teams to answer another team's Bonus Question if they answer incorrectly. If the box is left unchecked (the default setting), only the team that answered the previous question correct is allowed to answer the Bonus Question.