The Chief Information Security Officer $($CISO$)$ asked a security manager to set up a system that

sends an alert whenever a mobile device enters a sensitive area of the company's data center.

The CISO would also like to be able to alert the individual who is entering the area that the

access was logged and monitored. Which of the following would meet these requirements?

A$.$ Near$-$field communication

B$.$ Short Message Service

C$.$ Geofencing

D$.$ Bluetooth