Task: Question Generation
Input (English): In August 1939, a motley group of travellers find themselves in a small hotel in Bavaria, awaiting a delayed train to Switzerland. They include a "much married madcap American heiress", Amanda Metcalf-Midvani-Von Hoffsteader-Kelly, and Robert Condon, a wise-cracking American photographer.That evening, Amanda gets very drunk and is knocked unconscious. The following morning, badly hungover, she finds herself in a train compartment with Miss Froy, an elderly governess, and Baroness Kisling with her servants. Other travellers include Charters and Caldicot, English gentlemen returning to Britain for the test match, and 'Todhunter', an English diplomat 'larking about' with his mistress and Dr. Egon Hartz.When she wakes up, Miss Froy has vanished. Her fellow travellers deny seeing Miss Froy and declare that she never existed. Amanda begins to doubt her own mental condition. Amanda starts to investigate, joined only by a sceptical Condon. The train stops to pick up a badly burnt and heavily bandaged automobile accident victim. Shortly thereafter, a "Miss Froy" apparently reappears, but it is not her.The train resumes its journey and Amanda is attacked. Miss Froy's broken glasses are found and Condon now believes Amanda's story. They surmise that Miss Froy was lured to the baggage car and is being held captive - and that the heavily bandaged 'accident victim' is now Miss Froy. This proves to be the case and Dr. Hartz attempts to drug them - but his wife (disguised as a nun) has not put any drug in their drinks.At the next station, the train is shifted onto a branch line and only the buffet car and one carriage are left. The train stops and Helmut von Reider, an SS officer (son of Miss Froy's former employer), approaches the train, demanding that Miss Froy be surrendered. The passengers refuse and a gunfight ensues. Miss Froy chooses this moment to confess that she is in fact a courier with a vital coded message (she hums a tune to them) that must be delivered to London. She leaves the train and disappears. Condon, Charters and Caldicot contrive to take over the engine and drive the train back to the main line and over the Swiss border. Back in London at the Foreign Office, the duo attempt to remember the tune she sang, then suddenly they hear someone humming the same tune. It is Miss Froy who managed to escape her captors.
Output (English): Question: on what instrument does gilbert hear the melody?, Answer: Miss Froy hums the tune.