A guesthouse reported the theft of 100,000 yuan in cash. After careful investigation, the public security personnel concluded that the front desk manager, Li, did. The director said: "This is impossible. " Then, no matter how unlikely it seems, it must be true. ". Which of the following, if true, is the most powerful argument for weakening public security personnel? ['It is virtually impossible for a police officer to know his manager better than the director.', 'The basis for punishing illegal acts cannot be logical reasoning, but only evidence.', 'Public security personnel cannot exhaust all possibilities.', 'Lee is recognized as an excellent manager of the guest house.']