Final answer:
Given the conditions, 'Nights All Right' is on the keyboard and 'Rhino Rock' is played after 'Question Man', leaving only 'Sammy' to be performed on the flute.
Step-by-step explanation:
The question indicates that each of the four songs is played on a different instrument, with specific conditions for each song. Since 'Nights All Right' is performed on the keyboard, it cannot be the song played on the flute. 'Sammy' cannot be performed on the guitar or harmonica, which leaves only the flute or keyboard, but since the keyboard is taken by 'Nights All Right', 'Sammy' must be performed on the flute. Finally, since 'Rhino Rock' is performed immediately after 'Question Man', neither of them can be played on the flute if 'Sammy' is being performed on that instrument. The song performed on the flute is Sammy.