When considering a database that contains sensitive information, securing 'Data at rest' is essential. Encrypting data at rest means protecting the data while it is stored and not being processed or moved. This helps prevent unauthorized access to the data if the physical security of the storage medium is compromised. While data in transit and data in use are valid data states, they refer respectively to when data is moving through the network and being processed in memory, not when it is stored. Encrypted storage, on the other hand, is a broad term that includes data at rest but does not pinpoint the state itself.