In RBAC, access is based on the roles that users have within an organization, and permissions to perform certain operations are assigned to specific roles. DAC, on the other hand, is a type of access control where the access rights are determined by the owner of the resource or the resource itself.

SQL injection is a type of vulnerability that allows an attacker to execute malicious SQL statements on a database server. This can result in reading, writing, or erasing information from the database, as well as bypassing authentication, executing commands, or compromising the server. SQL injection exploits the lack of input validation or output encoding in web applications that interact with databases. References := Cisco Cybersecurity Operations Fundamentals, Module 1: Security Concepts, Lesson 1.3: Common Network Application Operations and Attacks, Topic 1.3.2: Web Application Attacks

When a server is experiencing heavy CPU and memory load, the initial step is to identify the processes consuming the most resources. The command "ps -ef" provides a detailed view of all running processes, including their IDs, CPU, and memory usage, which helps in pinpointing the resource-intensive processes1234. References: This approach is supported by various resources on server management and troubleshooting, which recommend using the "ps -ef" command as a starting point for investigating high resource usage on servers

The difference between tampered and untampered disk images is:
Tampered Images: These are disk images that have been altered or modified in some way after their initial creation. The stored hash and the computed hash will not match if the image has been tampered with.
Untampered Images: These are disk images that have not been altered since their creation. They are considered authentic and reliable for forensic investigations. The stored hash and the computed hash will match, confirming that the image has remained unchanged.
Therefore, the correct answer is: D. Untampered images are used for forensic investigations.