A company has drafted an insider-threat policy that prohibits the use of external storage devices.
Which of the following would BEST protect the company from data exfiltration via removable media?
A . Monitoring large data transfer transactions in the firewall logs
B . Developing mandatory training to educate employees about the removable media policy
C . Implementing a group policy to block user access to system files
D . Blocking removable-media devices and write capabilities using a host-based security tool
Answer: D