7. An investigator is drafting an outline for questioning a witness who is defending a public crime. He intends to ask only such questions that can be answered with a "yes" or "no" (of course, whether to ask a certain question depends on the witness's answer to the previous question). The investigator believes that all answers will be truthful, and he estimates that, under any questioning outcome, the number of questions asked will not exceed 91.

Try to explain: The investigator can draft a questioning outline that does not exceed 105 questions, to cope with the possibility that the defense witness might give an untruthful answer to any one question (of course, it is also possible that all answers are truthful).

Note: If you can only draft an outline with more than 105 questions, then please provide the best solution you can come up with.