Which of the following are common methods to control a building's access?

• A. Card readers
• B. All of the above
• C. Guards
• D. Locks

Answer: (B)

Access control for a building is usually achieved with multiple layers that verify who can enter and when. Locks provide the basic physical barrier, stopping entry without the proper key or mechanism. Card readers add an electronic check, verifying credentials and unlocking doors for those with permission while keeping an audit trail of who accessed where and when. Guards add a human layer, capable of verifying identities, challenging suspicious individuals, and responding to incidents or changes in real time. When these controls are used together, they create defense in depth: if one line of defense is bypassed, the others still help protect entry points. That’s why common methods include all of these, making the integrated approach the most effective for controlling access.