Passage: Given the many and varied elements and styles of melody "many extant explanations [of melody] confine us to specific stylistic models, and they are too exclusive." Paul Narveson claimed in 1984 that more than three-quarters of melodic topics had not been explored thoroughly.The melodies existing in most European music written before the 20th century, and popular music throughout the 20th century, featured "fixed and easily discernible frequency patterns", recurring "events, often periodic, at all structural levels" and "recurrence of durations and patterns of durations".Melodies in the 20th century "utilized a greater variety of pitch resources than ha[d] been the custom in any other historical period of Western music." While the diatonic scale was still used, the chromatic scale became "widely employed." Composers also allotted a structural role to "the qualitative dimensions" that previously had been "almost exclusively reserved for pitch and rhythm". Kliewer states, "The essential elements of any melody are duration, pitch, and quality (timbre), texture, and loudness. Though the same melody may be recognizable when played with a wide variety of timbres and dynamics, the latter may still be an "element of linear ordering"

Question: What did Kliewer see as the most crucial aspects of a melody?
duration, pitch, and quality (timbre), texture, and loudness