Biometric access-control systems—those using fingerprints, voiceprints, and so forth, to regulate admittance to restricted areas—work by degrees of similarity, not by identity. After all, even the same finger will rarely leave exactly identical prints. Such systems can be adjusted to minimize refusals of access to legitimate access seekers. Such adjustments, however, increase the likelihood of admitting impostors.

Which of the following conclusions is most strongly supported by the information above?

• AIf a biometric access-control system were made to work by identity, it would not produce any correct admittance decisions.  
• BIf a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers.  
• CBiometric access-control systems are appropriate only in situations in which admittance of impostors is less of a problem than is mistaken refusal of access.  
• DNo biometric access-control systems—based, for example, on numerical codes—are less likely than biometric ones to admit impostors.  
• EAnyone choosing an access-control system should base the choice solely on the ratio of false refusals to false admittances.