What is the primary function of a turnstile in entry control?

• A. Allows single person entry with controlled unlock.
• B. Allows multiple people through at once.
• C. Verifies biometric data.
• D. Blocks all entry unless security approves.

Answer: (A)

The main idea here is that a turnstile is a physical barrier that enforces one-person-at-a-time passage and unlocks only for a verified entry. When someone presents a valid credential to the access control system, the turnstile releases and allows a single person to pass, while blocking others from following through immediately. This setup helps prevent tailgating and provides an automatic record of who entered and when. Verification of identity is typically handled by separate readers or biometric sensors tied to the access system, but the turnstile’s job is to grant passage in a controlled, single-file manner. It isn’t designed to allow many people at once or to block everyone unless security approves every entry; instead, it unlocks for authorized individuals and maintains order and accountability at the doorway.