Firewalls and strong passwords are logical security measures that protect digital infrastructure by controlling access and authentication.

The best option for the database administrator to use to update an organization's ERD is a UML tool. A UML tool is a software application that allows users to create, edit, and visualize diagrams using the Unified Modeling Language (UML). UML is a standard language for modeling software systems and their components, such as classes, objects, relationships, behaviors, etc. UML can also be used to create entity relationship diagrams (ERDs), which are graphical representations of the entities (tables), attributes (columns), and relationships (constraints) in a database. A UML tool can help the administrator to update an organization's ERD by providing features such as drag-and-drop, templates, symbols, validation, etc. The other options are either not suitable or not optimal for this task. For example, a word processor is a software application that allows users to create and edit text documents; a spreadsheet is a software application that allows users to organize and manipulate data in rows and columns; an HTML editor is a software application that allows users to create and edit web pages using HyperText Markup Language (HTML).

The option that is used to hide data in a database so the data can only be read by a user who has a key is data encryption. Data encryption is a process that transforms data into an unreadable or scrambled form using an algorithm and a key. Data encryption helps protect data from unauthorized access or modification by third parties, such as hackers, eavesdroppers, or interceptors. Data encryption also helps verify the identity and authenticity of the source and destination of the data using digital signatures or certificates. Data encryption can be applied to data at rest (stored in a database) or data in transit (transmitted over a network). To read encrypted data, a user needs to have the corresponding key to decrypt or restore the data to its original form. The other options are either different concepts or not related to hiding data at all.
For example, data security is a broad term that encompasses various methods and techniques to protect data from threats or risks; data masking is a technique that replaces sensitive data with fictitious but realistic data to protect its confidentiality or compliance; data protection is a term that refers to the legal or ethical obligations to safeguard personal or sensitive data from misuse or harm.

The ORM snippet that would return the ID, state, and country of all customers with the newest customers appearing first is option C. This snippet uses the select method to specify the columns to be returned, the order method to sort the results by ID in descending order, and the all method to fetch all the records. The other options either have syntax errors, use incorrect methods, or do not sort the results correctly. References: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective
1.2 Given a scenario, execute database tasks using scripting and programming languages.

CO2 systems are fire suppression mechanisms that are triggered by high temperatures, which can occur after a power failure disables cooling systems and causes equipment to overheat.