Nearly all the music heard at an orchestral performance today contains pitch relationships that do not precisely match those that musical instruments naturally produce. This is because the members of a modern orchestra read musical notation that, more than 99% of the time, represents a tempered system of tuning. In the tempered system, certain pitch relationships are slightly altered from those that naturally occur in vibrating bodies such as musical instruments. In non-tempered tuning systems, these relationships are not altered.
Which of the following, if true, most strengthens the argument?
Because of lifelong exposure to tempered tuning systems, most people perceive music written using non-tempered tuning systems as being out-of-tune.
Orchestra musicians always play music exactly as it is notated.
The tempered tuning system is used by the vast majority of jazz and rock musicians.
The standard orchestral repertoire is drawn from music written during the last three centuries, during which time composers have almost always used musical notation that represents the tempered system of tuning.
The tempered system of tuning allows musicians to make key changes more easily than does the non-tempered.