This compositional method is the ultimate postmodern musical experiment, involving an unpredictable sequence of events that results from non-musical decisions (rolling dice, choosing cards, astrological charts,
a. chance musicb. electronic musicc. twelve-tone compositiond. sprechstimmee. polytonality

chance music

Explanation:

Chance music is a musical style developed in the twentieth century that seeks greater freedom by playing with a degree of unpredictability and luck, both during the composing process, in the performing process, or at both times.

In general, in this type of composition, the performer is presented with several alternatives, and it is up to him to choose which notes or which part of the music will play and in what order. The height of banknotes may be indicated but not their duration, or vice versa. You can also contribute notes of your own choosing by improvising. There are pieces where notes are not even provided, just a series of symbols, a diagram, a drawing, or nothing more than an idea. Everything can be freely interpreted.