The correct answer is Full-Disk Encryption (FDE) because it encrypts the entire hard drive of the laptop, including the operating system, and ensures that all data on the device is protected. This is most effective for devices like laptops that can easily be stolen or misplaced, protecting against unauthorized access even if the laptop is turned off.

Partition encryption would only encrypt a specific partition of the hard drive, which means sensitive data stored outside of this partition would not be protected. File-level encryption would protect individual files, but it would not necessarily secure system files or temporary files that could contain sensitive data. Database encryption focuses on protecting data within a database and is not typically applied to the entire storage system of a laptop.