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

SIGPIPE is sent when a process attempts to write to a broken pipe; it is not used to request process termination.

SIGKILL (signal 9) immediately and unconditionally terminates the process - it cannot be caught, blocked, or ignored, so no cleanup is possible.

SIGSTOP suspends (pauses) the process rather than terminating it; the process remains in memory and can be resumed with SIGCONT.

SIGTERM (signal 15) is the default termination signal and can be caught by the process, allowing it to run signal handlers that close files, release resources, or save state before exiting. This is distinct from forced termination because the process retains control over how it shuts down. kill -TERM 123 sends SIGTERM to PID 123, fulfilling the requirement for a clean shutdown.