Which command can be used to view the active processes in the system?

The command that can be used to view active processes in the system is indeed a broad category, and all the listed commands are capable of providing information about active processes.

The ps command is commonly used to display a snapshot of current running processes along with their attributes, such as process ID (PID), terminal, CPU time, and command name. It can be customized with various options to filter the processes displayed, making it a versatile choice for process monitoring.

The top command offers a dynamic, real-time view of active processes and displays them in an ongoing list, updating continuously. It provides crucial information such as CPU usage, memory consumption, and process priority, allowing users to monitor system performance effectively.

The pstree command displays a hierarchical view of processes, showing how processes are related to one another in terms of parent and child relationships. This command helps visualize the structure of process creation, which can be particularly useful in understanding how processes are organized.

Given that each of these commands serves the purpose of viewing active processes, selecting the option encompassing all of them reflects a comprehensive understanding of process management in Linux systems.