Lisa wants to ensure that theft of a device will not lead to exposure of the data contained on the device if the device is locked or turned off. What type of encryption should she select to best ensure this?

Full-disk encryption provides the most security in situations like this if the device is locked or off. Volume- and partition-level encryption may leave some drive information or even entire volumes or partitions unencrypted, and file-level encryption is typically selective instead of covering every file on a drive.