Final answer:
The BEST method to prevent unauthorized users from obtaining proprietary information on a lost mobile device is to implement remote wipe.
Step-by-step explanation:
The BEST method to prevent unauthorized users from obtaining proprietary information on a lost mobile device is to implement remote wipe. Remote wipe allows the employee or the company to erase all data on the device remotely. This ensures that even if the device falls into the wrong hands, the proprietary information cannot be accessed.
Other options like lock screen pattern and six-character password provide some level of security, but they can still be bypassed or cracked. Canceling mobile service does not directly prevent unauthorized users from obtaining the information on the device.