What command can be used to end a running process by its ID?

The command that can be used to end a running process by its ID is "kill." This command is specifically designed to send signals to processes, and one of the most common uses is to terminate a process. When you provide the process ID (PID) as an argument, the kill command sends a default signal (SIGTERM) to the specified process, requesting it to terminate gracefully.

In practice, if a process does not respond to the default termination signal, you can also specify other signals with the kill command (for example, using kill -9 to send SIGKILL, which forces the termination of a process). This versatility makes the kill command a fundamental tool for managing processes in Linux.

The other options such as "stop," "terminate," and "end" do not correspond to standard commands used in the Linux command line for terminating processes, and therefore would not be effective for this purpose.