A User's Laptop Hard Drive Contains Sensitive Information

Multiple Choice

A user's laptop hard drive contains sensitive information. The user often plugs the laptop into the corporate network. A sensitive file from the laptop has been found on another user's laptop. How could the user have prevented this breach?  

A) Disable file and print sharing on the laptop.
B) Delete unused drives from network.
C) Remove shared keys from the key ring.
D) Set the read-only attribute on the files.