If a train stops on a controlled track, what is the initial radio announcement required?

Answer: A — Train has stopped.

When a train stops on a controlled track, the first radio message should plainly report the stop to establish occupancy and elicit the next steps from the dispatcher. Saying “Train has stopped” communicates the exact status immediately and lets the dispatcher know where the train is not moving, so they can manage signals, authority, and any required follow‑up actions. The other options either imply a status that isn’t yet confirmed (the track is clear), are redundant because notifying the dispatcher comes from reporting the stop, or don’t apply to stopping on a controlled track (like confirming station arrival).