Answer:
b. a technique of playing more than one note at a time on a wind instrument
Explanation:
Multiphonics -
It is one of the technique on the monophonic musical instrument , where various notes are produced at one go , is referred to as multiphonics .
The various notes includes , human voice , brass , reed , wind etc , in this technique .
The method is adapted to make playing the instrument in a very innovative manner , by using many notes .
Hence , from the given scenario of the question ,
The correct answer is b.