Which of the following commands kills the process with the PID 123 but allows the process to "clean up" before exiting?

There is no standard `SIGPIPE` signal intended for process termination; `SIGPIPE` typically occurs when writing to a pipe or socket with no reader.

The `kill -KILL` command sends the `SIGKILL` signal (signal 9), which immediately terminates a process without allowing it to perform any cleanup operations, as it cannot be caught or ignored.

The `kill -STOP` command sends the `SIGSTOP` signal (signal 19), which pauses or suspends a process without terminating it, allowing it to be resumed later with `SIGCONT`.

The `kill -TERM` command sends the `SIGTERM` signal (signal 15) to a process, which is a request for graceful termination. This allows the process to catch the signal, close files, save state, and exit cleanly.