To protect confidential financial information on a laptop that is frequently moved between locations, full disk encryption (FDE) is a strong security measure that ensures that all data on the hard drive is encrypted. This means that if the laptop is lost or stolen, the data remains inaccessible without the encryption key. Additionally, backing up the file to an encrypted flash drive provides an extra layer of security and ensures that there is a secure copy of the file in case the laptop is compromised.