I notice that while the quiz writer was fastidious enough to put the exclamation mark on "Oliver!", he/she was not quite fastidious enough to do the same for "Oklahoma!".
I hate to be a pedant but I don't think an octave is 8 notes because note doesn't really mean anything - a much better description would be "an interval of 12 semitones"
Better pedantry- the interval of 12 semitones is a function of the development of equal temperament in the 18th century; before that, the octave was thought of as 8 tones (hence oct-ave) which could be sharped or flatted.