The Read Uncommitted isolation level allows dirty reads, meaning transactions can read data that has been modified but not yet committed by other transactions.

The NoSQL database type that best categorizes MongoDB is document. Document databases are databases that store and manage data as documents, which are collections of fields and values in formats such as JSON (JavaScript Object Notation) or XML (Extensible Markup Language). Document databases do not use any schema or structure to organize data, but rather use identifiers or indexes to enable flexible and dynamic access to data based on fields or values. Document databases are suitable for storing large amounts of complex or unstructured data that have variable attributes or nested structures. MongoDB is an example of a document database that uses JSON-like documents to store and query data. The other options are either different types of NoSQL databases or not related to NoSQL databases at all. For example, column-oriented databases are databases that store and manage data as columns rather than rows; graph databases are databases that store and manage data as nodes and edges that represent entities and relationships; key-value stores are databases that store and manage data as pairs of keys and values. Reference: CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.1 Given a scenario, identify common database types.

The correct answers are A. Firewall and B. Strong passwords. CompTIA DataSys+ differentiates security controls into logical (technical) and physical infrastructure security measures. Logical security measures are implemented through software, configuration, and system controls to protect data, systems, and network resources from unauthorized access or misuse.
A firewall is a core logical infrastructure security control. It enforces security rules that regulate incoming and outgoing network traffic based on predefined policies. In database environments, firewalls are used to restrict access to database servers, limit exposed ports, and allow connections only from trusted IP addresses or networks. DataSys+ emphasizes firewalls as a first line of defense in protecting databases from unauthorized access and network-based attacks.
Strong passwords are another essential logical security measure. They are part of authentication controls that ensure only authorized users can access systems and databases. Strong password requirements-such as minimum length, complexity, expiration, and reuse restrictions-help mitigate attacks like brute-force attempts, credential stuffing, and unauthorized privilege escalation. DataSys+ highlights strong authentication controls as foundational to protecting database environments.
Option D, port security, can be ambiguous, but in CompTIA context it is often associated with network switch configurations and is more infrastructure-specific; however, the exam most clearly classifies firewall and authentication mechanisms as logical controls. Options C, E, and F-key cards, camera systems, and time locks-are all physical security controls. These protect the physical facility or hardware but do not directly enforce access through software or system logic.
CompTIA DataSys+ stresses a layered security approach, where logical controls protect data and systems, while physical controls protect facilities. In this question, the focus is explicitly on logical infrastructure security, making Firewall and Strong passwords the most accurate and clearly aligned answers.
Therefore, the correct selections are A and B.