8. A method as in claim 7 , wherein a policy of the set of policies includes a rule concerning an amount of time within which a KBA question of the selected KBA questions that was provided to another person is not to be provided to the person; wherein selecting the selected KBA questions includes: not including a KBA question of the set of KBA questions in the selected KBA questions when the KBA question was provided to the other person within the amount of time, and including the KBA question in the selected KBA questions when the KBA question was provided to the other person outside of the amount of time.
8. A method as in claim 7 , wherein a policy of the set of policies includes a rule concerning an amount of time within which a KBA question of the selected KBA questions that was provided to another person is not to be provided to the person; wherein selecting the selected KBA questions includes: not including a KBA question of the set of KBA questions in the selected KBA questions when the KBA question was provided to the other person within the amount of time, and including the KBA question in the selected KBA questions when the KBA question was provided to the other person outside of the amount of time. 9. A method as in claim 8 , wherein a policy of the set of policies assigns weights of a set of weights to KBA questions of the set of KBA questions; wherein selecting the selected KBA questions includes: choosing, as the selected KBA questions, a predetermined number of KBA questions to which weights having the largest values are assigned.