Which type of composition is specifically written for a choir?

A choral composition is specifically crafted for a choir, which consists of multiple vocal parts that are designed to be sung together harmoniously. These compositions can vary in style, including sacred, secular, classical, and contemporary music, and they typically utilize the unique capabilities of choral voices to create rich textures and harmonies.

The writing of a choral piece involves considerations for vocal ranges, the integration of different voice types (soprano, alto, tenor, bass), and the blending of these voices to achieve a cohesive sound. Such works may include various forms, such as anthems, motets, or larger choral works like oratorios.

In contrast, solo pieces are intended for individual performers, instrumental arrangements focus on music adapted for instruments rather than voices, and harmony refers to the combination of different musical notes played or sung simultaneously. These options do not fulfill the specific requirement of being composed for a choir, thus underscoring why choral composition is the correct answer.