Which device is used to grant or deny gate access based on credentials?

• A. Pushbutton light switch
• B. Access card reader
• C. Motion sensor
• D. Water sensor

Answer: (B)

Credential-based access control gates hinge on verifying a user's credential before granting entry. An access card reader does exactly that: it reads a card or fob, checks the credential against an authorization system, and signals the gate controller to open if valid or to deny if not. This enables automated control, event logging, and enforcement of time or user-based restrictions. In contrast, a pushbutton light switch is a manual actuator, a motion sensor triggers action based on movement, and a water sensor detects liquid presence—none of these verify credentials. Therefore, the device used to grant or deny gate access based on credentials is the access card reader.