What is a defining feature of 12-tone music?

• A. Use of a tone row that contains all twelve pitch classes in some fixed order before repetition.
• B. Reliance on traditional tonal centers and functional harmony.
• C. Frequent use of microtonal intervals.
• D. Monophonic texture with a single melodic line.

Answer: (A)

A defining feature of 12-tone music is using a tone row that contains all twelve pitch classes in a fixed order before repetition. This means the composer selects an ordered sequence of every distinct pitch (the twelve semitones in an octave) and then builds the piece from that row, ensuring no pitch is heard again until all twelve have been presented. This approach treats all pitches equally and prevents establishing a traditional tonal center.

In practice, the tone row can be varied through transformations like inversion (reversing the intervals), retrograde (reading the row backward), retrograde-inversion, and transposition, which allows creative variety while preserving the rule that all twelve tones come before any repeats.

The other options describe features not specific to 12-tone technique: relying on traditional tonal centers and functional harmony belongs to tonal music; microtonal intervals involve pitches outside the standard twelve-tone system; and monophonic texture refers to a single melodic line, which is not what defines 12-tone music.