In biometric, a match occurs when a ________ meets the decision criteria.

• A. set of key features
• B. Both A and B
• C. Neither A nor B
• D. match index

Answer: (D)

In biometric decision making, the result of comparing an input sample to a stored template is represented by a match index, a metric of similarity. The system computes this index from the extracted features and then checks whether the index meets the predefined decision criteria (the threshold). A match is declared only when this index passes the threshold. So the element that actually satisfies the decision criteria is the match index, not just the raw features alone. The set of key features is what the system uses to compute that index, but it’s the index value itself that determines a match.