What characterizes "idiomatic" writing in music composition?

Idiomatic writing in music composition is characterized by exploiting the unique characteristics of specific instruments. This approach involves taking advantage of the particular timbres, technical capabilities, and expressive potential of each instrument. Composers who engage in idiomatic writing tailor their musical ideas to suit the strengths and distinctive qualities of the instruments for which they are writing. For instance, a piece for piano might utilize rapid passages or intricate fingerwork that enhance the instrument's capabilities, while a composition for violin might focus on techniques such as vibrato or harmonics that highlight the violin's expressiveness.

The other options do not capture the essence of idiomatic writing. Composing for multiple genres may show versatility, but it does not directly relate to the tailored approach of idiomatic writing. Writing for large orchestral groups only pertains to ensemble size rather than the individual characteristics of instruments. Simplifying complex musical pieces refers to stylistic choices rather than focusing on the idiomatic features of the instruments themselves. Thus, the exploitation of each instrument's unique traits is the hallmark of idiomatic writing in music composition.