How do you answer if you've ever been discharged on a job app?

My wife was fired from her previous job as a banker due to an error made while opening an account. This caused the bank money and she was subsequently fired. Now she has been contacted by other banks for interviews. How should she handle this? Should she state "yes" on the app or "no". If "yes", what should she write on the app and say during the interview regarding being let go from the previous banking job?