The correct option is b.
The music excerpt is an example of polyphonic texture, where multiple independent melody lines are played simultaneously; this became prevalent in the Ars nova period of the high medieval era.
The music excerpt described in the question is an example of polyphonic texture. Polyphonic texture, also known as counterpoint, is a style of musical composition in which two or more independent melody lines are played simultaneously. This texture became prevalent during the high medieval era, often associated with the Ars nova period, which saw the flourishing of polyphony in both sacred and secular music. In contrast, monophonic texture refers to a single melody line with no accompaniment, which characterized much of the earlier medieval music, including Gregorian chant. Cacophonic texture is a dissonant sounding of notes that can exist in music but is not a standard term used in describing musical textures. Homophonic texture involves a primary melody with chordal accompaniment and is different from the independent lines of polyphonic music.